THanks for all the replies, everyone.
It's getting a lot better now--I guess it just has to take its course. There were about two days though, where the pain was fairly unbearable, as every once in a while I'd get these waves of pain that gave me flushes and everything. Eating was pretty much undoable.
I'm pretty sure I'm one of the luckier ones, in that I don't get chronic sores. I think this one was caused by me trying to be fastidious in my dental hygiene, as I still have my wisdom teeth and was trying to clean one of them. I think I irritated the cheek tissue above the tooth, and my immune system must have just freaked out. I don't think I was nutritionally deficient... I've been taking the exact same supplements for about 5 months now without missing a day (A, B-complex, C, E, Niacin, Zinc, Garlic, Multi, etc.). Of course, vitamin absorption is another thing, but I am pretty healthy.
As far as what helped, I'm not too sure. For the actual malady, I took lots of acidopholus, and only did anti-bacterial mouthwashes in the morning and at night, with baking soda and/or salt. One of the first things I did when it really started to hurt was to grind in some salt into the sore, and man oh man, that was some serious pain. Just waves and waves of pain. I'm not sure if it did any good. For the ongoing pain, I tried putting baby aspirin tablets directly on the sore (crushed tablets), but that didn't really help. I took tylenol and that helped the general pain around my head and neck. THe best thing, I think, that eased the pain at the site of the sore was cold ice water, and maybe a little piece of ice held up against it. That would at least numb it for a while when I ate.
Anyway, it seems to be going away now, the inflammation is receding, and the general pain is greatly subsiding.