Second motion on Pyralvex.
Best to use just before lunch or dinner (or whenever you eat for that matter). It hurts so much you better brace against something before putting it on. I am not kidding, even if you don't fall down, this'll still bring tears to your eyes. The good side tho is that once the pain fades, your lips go numb and you can eat normally.
My family is partially diabetic, so mouth sores are common and we've got bottles of it stashed away.
There's another one. I can't remember the name, i'll post it after i remember. It's a clear (or white) liquid. Doesn't hurt at all and sores heal much faster. But it doesn't make the sore go numb so eating still hurts, we went back to pyralvex because of that.