Show them to a Shaman and ask if she thinks they are those "herpes I" or "apthous ulcers."
(This may be more courtesy than anything else, they're not all that easy to tell apart. Your dentist may be better at doing that, and if you have the virus latent within you, going to the dentist can pop it right up).
If you have a hunch they're viral in origin, encourage the Shaman to agree, and give you some acyclovir.
There's an over the counter thing now, called Abreva, which actually works better than acyclovir ointment if they're on your lips, but you can't put ointment in your mouth. (Well, you
can, but it won't stay put long enough to help).
If the acyclovir
does clear them up, take a bottle of it every 3 or 4 months and you can keep them gone. You can also tell your dentist you're prone to them, and she'll start giving you a prescription for acyclovir along with your new toothbrush every visit, because going to the dentist will invoke the most dormant Herpes I spirits!
If the acyclovir doesn't clear them up, they might be apthous ulcers, which are trickier and you can ask for some steroids, and try taking a lot of B12.
I think they used to treat apthous ulcers with silver nitrate, I wonder if they still do?
What's interesting in this context, though, is if you look up apthous ulcers in Wikipedia (I know. I said interesting, not reliable) it mentions something about treatment with MAO inhibitors having become controversial.
Haven't there been some articles about MAO inhibitors being in cigarette smoke?
Just filing that under "Things That Make You Go Hmmm"
Whatever it is or isn't, you could also ask for a little bottle of lidocaine to calm them down during the worst part.