My fianc has MS and when he had this sensation they put him on intravenous steroids for a week or so. I am unsure if this is the response you were looking for...

good luck!!! I have had the burning in my legs for along time nothing helps much. I take neurotin 300mg 3x a day, helps a LITTLE bit, helps more with the restless leg issues. If you find out let me know.

I had had over years, occassional bilateral burning pain-re: two arms or two legs, or two breasts, or two shoulders. It rotates to other bilateral body parts during attacks. Recently had the mouth,tongue, lips-first time in 23 years. And I'm also wondering what part of the brain or brain stem malfunction causes this burning.
I wonder if using a cool pac on the back of the neck might help, don't know.
I hope that mouth burning goes away real quick, hugs.