This is going to take a while--it's a big thicket, with dozens of plants, though Patrick has cleared out a fair-sized bare patch. If he keeps on going, there's a substantial chance of a botch.
His Intuition does however tell him that his actions are harming the forest, and the connection becomes weaker as he proceeds with his handiwork.
Scott
Junkie-trembles shaking his entire body, he mentally promises to put all those plants back when he's done today. Maybe with a nice long ceremonially spell...
For now, he steps into the clearing he's made, and feels for that chill again.
It's still there. In fact, it's stronger now.
Scott
Stronger because I'm further in, or stronger in the spot I stood on before?
In the same spot. To clarify, what's stronger is that chill--the sense, perhaps, that something is very amiss.
Scott
Does the chill get stronger as he goes deeper in?
(OOC: Starting to feel at a loss for what else to do. Can you give me any hints, based on his skills?)
It gets stronger, yes.
As for what to do....Try going deeper? 
Scott
~headdesk~ Communication failure.
Yes, he goes deeper into the thicket.
[Well, you kept circling the perimeter....]
After a few more steps, the environment changes, just enough to be noticeable. The plants appear...different, somehow, and just a little sinister, while the air now hangs more heavily.
Scott
Oh, no. I agree, totally my miscommunication there.
Patrick utters the name of a saint under his breath like a curse, and performs his Lucky, Lovely, Hosed and Screwed rotes again, starting with Screwed (testing for Infernal Aura Strength). (Casting Total 14 + Aura/2 vs InVi3)
When he's done with that, he'll spont a regio-boundary detector spell.
Base 3, +2 Smell, roll up for Duration = InVi 5
In 9 + Vi 5 + Sta 2 + Aura ? + die 2 = 18 + Aura /2 = 9 + Aura/2
This will possibly give him a momentary sniff of the way back out.
The aura is still infernal, it's stronger, and yes, it's a regio--and yes, Patrick can get back out if he wants, as he's able to detect the boundary.
Scott
Patrick ease back out of the regio and then mark the entrance. He'll retreat further until he is back in a positive aura.
Eyeing the shadows to determine the time, he tries to determine if the covenant is with Arcane Line distance, but then decides that even if it was, he probably wouldn't be able to do the math. Thinking harder, he recalls the single tower always has a man on guard there, and that one of his Significant Lamp Circles is in that same room. Would he count as an Arcane connection to the spell he wrought so long ago? On the one hand, he hopes that he might, but if it does, then there are some disturbing consequences....
"Damn my short-sightedness!" he curses aloud (pausing briefly to consider the implications of swearing so close to an infernal taint). "I should have an Arcane connection for this. It should be a standard procedure."
Well, there's nothing for it. He could reach Leon, but the hunter was off learning the local lore. He'll try this, and if it doesn't work, then he'll try to get some bird to run the message for him.
"Phantasmal Message"
CrIm, Base 1 (sound), R: +4 Arcane, D: +1 Diam, T: Ind, +1 Intelligible Speech = CrIm15
He knows that his target, the magic circle of The Significant Lamp in the guard's tower, is a perfect circle, making it a suitable target for Geometer's Ceremonial bonuses.
Geometer’s Ceremony ( TMRE 94), 45 minutes : Cr 9 + Im 5 + Sta 2+ Aura _ + Artes Liberales 5 + Philosophiae 3 + Numero/Geometric Correspondences 3 + Lines or Circles 3 + 4 Numerology Book + 4 Talisman attunement (Numerology) + die = 38 + Aura + die 1, die 2 = 42+ Aura / 2 = 21+ (Aura/2)
Addiction die roll +5 : 11 vs 8
Assuming his target is valid, then he'll be able to transmit a diameter's worth of speech. Does the guard even speak Latin? So poorly thought out.... "Okay, now don't be scared. This is Patrick the Unrepentant, and I just need to report in. I've found an infernal regio down in the delta, and am going to investigate. If I don't come back, then ask the herons to show you where I am. Tell Tasia. I'm sorry if I spooked ya."
And then, despite all that work, he still feels as if there are too many unknowns, and so tries to find an animal he can talk into delivering a scrap of paper to the covenant.
It might be an Arcane connection to him, but not he to it (obviously, he's more significant to an item that he's enchanted than vice versa).
That he can manage, and he finds the aid of a friendly songbird.
Scott
After dispatching the friendly song bird (and reminding himself that he really ought to train some birds to work for the covenant), he will re-plant all those bushes which he ripped out earlier, attempting to combine his numerology, magic theory and hunting skill to replant them in a mystically significant way which will combat the infernal aura (not sure if that's going to be any more effective than some kind of folklore-esque solution, but...)
invisiblecastle.com/roller/view/3435684/
(Same rolls as earlier, vs ReHe 10)
1d10.open(10)+22;1d10.open(10)+5 → [1,22] = (23)
1d10.open(10)+22;1d10.open(10)+5 → [[10, 2],5] = (17) Non-botch Addiction roll still succeeds
1d10.open(10)+22;1d10.open(10)+5 → [2,22] = (24)
1d10.open(10)+22;1d10.open(10)+5 → [3,5] = (8)
1d10.open(10)+22;1d10.open(10)+5 → [1,22] = (23)Explodes! Additional die pointless.
1d10.open(10)+22;1d10.open(10)+5 → [7,5] = (12)
1d10.open(10)+22;1d10.open(10)+5 → [9,22] = (31)
1d10.open(10)+22;1d10.open(10)+5 → [1,5] = (6) Explodes! Additional die pointless.
1d10.open(10)+22;1d10.open(10)+5 → [7,22] = (29)
1d10.open(10)+22;1d10.open(10)+5 → [7,5] = (12)
1d10.open(10)+22;1d10.open(10)+5 → [7,22] = (29)
1d10.open(10)+22;1d10.open(10)+5 → [6,5] = (11)
1d10.open(10)+22;1d10.open(10)+5 → [9,22] = (31)
1d10.open(10)+22;1d10.open(10)+5 → [1,5] = (6) Explodes! Additional die pointless.
1d10.open(10)+22;1d10.open(10)+5 → [9,22] = (31)
1d10.open(10)+22;1d10.open(10)+5 → [1,5] = (6) Explodes! Additional die pointless.
1d10.open(10)+22;1d10.open(10)+5 → [7,22] = (29)
1d10.open(10)+22;1d10.open(10)+5 → [4,5] = (9)
1d10.open(10)+22;1d10.open(10)+5 → [1,22] = (23) Explodes! Additional die pointless.
1d10.open(10)+22;1d10.open(10)+5 → [5,5] = (10)
1d10.open(10)+22;1d10.open(10)+5 → [7,22] = (29)
1d10.open(10)+22;1d10.open(10)+5 → [[10, 4],5] = (19)Non-botch Addiction roll still succeeds
1d10.open(10)+22;1d10.open(10)+5 → [4,22] = (26)
1d10.open(10)+22;1d10.open(10)+5 → [1,5] = (6) Explodes! Additional die pointless.
Placement of shrubs: Magic Theory, Math, and Hunt
invisiblecastle.com/roller/view/3435703/
1d10.open(10) → [8] = (8) Int +2 + Magic Theory 4 = 14
1d10.open(10) → [4] = (4) Int +2 + Artes Liberales(mathematics) 4(1) = 11
1d10.open(10) → [7] = (7) Int +2 + Hunt (track) 3 = 12
After that, he'll cast Doublet and Sidestep, pull out his sword and step into the regio to explore. He'll be extra-careful about marking the path back to the boundary.
Replanting the plants doesn't diminish the infernal aura, but Patrick nonetheless senses it's the right thing to do.
What strategy is he going to use to explore the regio?
Scott
I figured there would be no immediate effect on the infernal aura, but am imagining the placement of the shrubs to be like....um.... Feng Shui in the real world, or real world superstitions. It may or may not have an effect in the long term, but it seems like the right thing to do. The sort of solution that unGifted would use on the problem, if that makes sense.
I'm a city boy, so it is hard for me to imagine what an effective hunter would use to scout unfamiliar terrain. Thus, I am going on my habits of exploring at the beginning of a game of Civilization 
Also, I don't have a clear idea of what the terrain in the regio is. Are we still in a River Delta? Is the border at the edge of the regio, or is there geography to explore in every direction? Does any direction seem more important than another, for some reason (defensive terrain, etc)?
He'd break it down into sections. Starting with the the area around the boundary, he'll mark out a small-ish natural boundary and explore that, to sort of establish a beachhead. While doing this, he's both investigating and also looking for natural defensive positions he can fall back to.
Patrick is still in a thicket--in other words, he's surrounded by dense growth of bushes and small trees, and at times it's difficult to move without pushing them aside; a little exploring reveals that the closer he gets to the center of the thicket, the denser the plants are. Pushing inward, he finally finds himself in a place where, somehow, he can't move--not even backwards, in the direction from which he came.
Scott
Is he magically stuck, or just stuck in the thicket? Can he move at all? Defend himself? He'll throw out a few rotes (which take no penalty for being silent, no gestures).
What's the Infernal Aura Strength?
Is there any vis in sight?
(Both of those have a Casting Total of 14+Aura, versus target numbers 3 or 5)
If he can move enough to cast spells, he'll most likely spont a personal Ward Against Fire and then set the thicket on fire (using his Palm of Flame rote).
(I would argue that, given his Magic Addiction and earlier spells, he would have been casting ReHe spells to create paths for him long before he got stuck.)
Sorry for the delay--I got distracted.
He's not stuck, exaclty--he just can't move back in the direction he came--the plants are too thick. That, obviously, implies that they've somehow moved or grown to block him since he passed by. Yes, if he wants to go back that way, he can try some sort of ReHe (or other) spell to clear a path.
3, at this point.
No. But would you want it it there were?
OK,the plants are starting to burn....as the fire begins to spread, what does Patrick do next?
Scott