I've spent the afternoon researching and I've found some clues - none of which are very comforting. I looked into a bacteria named Serratia. Apparently it strikes Bufo Americanus in a similar way that my Woodhousei is experiencing with the red abscesses. Apparently intense fluctuations of temperature might contribute in bringing it about. If this is indeed what she's come down with, then it might've stemmed from an honest mistake on my part. Where I live it is darn cold during the winter, and I started to notice Petunia winding down and sleeping most of the day. But like I said, it gets DARN cold, so I put a lamp on her anyway just in case. About a month ago I adopted an adult bearded dragon which this kid didn't want anymore. I was slightly unprepared by not having an extra lamp, so I temporarily gave petunia's lamp to the dragon just until I could buy a new hood and bulb which I did within 48 hours of getting the lizard. So petunia got cold, as I didn't have the heat vent on full bore as it dries out tropical terrariums far too much. I gave her back the lamp, but she didn't even seem to notice it (she loves the lamp) so I took it off after a few weeks, thinking that perhaps it was best just to let it be and accept the winter. (It's her first by the way, I caught her in July.) I heard some animals needed that. Then I started to notice her "Drunken" wobble while I was feeding her and so I switched once again to the lamp. I just couldn't make up my mind what was best for her, as I never had to deal with the issue in my other reptiphibians nearly as much, if at all. I'm afraid that through these good intentions I really stressed her out, thus leaving her open for either the Serratia theory or the Red Leg theory. Add on top that the mites, and you can see the poor girl is having a rough time of it.

In reply to Royce, the substrate I used was repti-bark. I don't like it at all for the toad, as the area around her bowl gets soggy fast, and then it seems to spread to the other chips. Also, the chips are quite sharp and perhaps through a combination of a cut mixed with the gross bark, Petunia may have gotten infected. I don't know, as you can tell I overthink way bad. It's just I'm so worried, the scholarly books I consulted at the university mention several diseases with similar symptoms and they all say that it is more than likely fatal. I'm trying to get to a vet now, but even if she does pass away, at least I've learned a great amount to help prevent anything like that in the future.

P.S. I'm working on the photos, but I can't guarantee I'll find a bug. To tell you the truth, I'll be happy if I never see another one of those bugs again. There wasn't a whole lot of them, mind you, and most were living on Petunias favorite hide, a typical "Half-Log" you find in every pet store. I haven't cleaned that yet so maybe I can find one there. Just know that they were absolutely TINY and red. And as to the enclosure, I can recreate it in the photo with the same furniture, but it won't be the "Original" per say, as the bark is already in the garbage. Basically it is comprised of fake and synthetic stones including a wall upon which she can climbs or dig under...wait a minute! Perhaps the bark wasn't the cause, just something that made it worse! The natural stones may have harbored the mites! When I collected them I rinsed them in hot water for a couple minutes but that probably wasn't enough-it was only recently that I learned you have to bake them prior to putting in the enclosure. That's probably it, I didn't really think about it until I started to describe my tank. I had them sitting around since fall, and I only put them in about a month or so ago which is when all the trouble started. Yikes, I feel so bad. And to think that I thought she was the easiest out of all my pets! I just need to remember to learn from my mistakes.

Sorry for this long post, but it helps me to think things through.

Thanks all for your concern and wish her luck!