Hello,
I, too, had burning mouth syndrome a few years back (going through "the change")
and did my own research.
The one drug recommended for it, is klonopin. The generic version is "clonazepam."
I've been on it, off & on..
It's a long-acting 'form' of xanax....a benzodiazipine. (sp?)
Anyway, I think a small amount, morning and night, might help.
Do a little research online & put in the words, "burning mouth syndrome and klonopin" and you'll see what I mean. It's the drug of choice for that particular problem.
I'm taking it for entirely different reasons now, but it's wonderful for that weird burning thing, some women seem to experience.
Hope I helped.
Let me know how you're doing.
S.

I'm a firm believer it's "stress" that causes it, plus maybe hormonal changes in one's body--men have hormonal issues, too.

I'd ask your doc about the klonopin, since the xanax is working, somewhat. It's much like xanax, but lasts longer in your body. I take .25 up to .5 in the morning & at bedtime. Without it, I have tongue/burning issues in my mouth. It all started with some major stress I had about 6 years ago... I didn't receive relief, until I started clonazepam (generic klonopin...relatively cheap). I went off of it for a couple of years, until recently, when I had a major health issue arise. I'm back on it, and it's helped a great deal.

Good luck.
S.