it could be Tri-geminal-neuralgia. it is the 7th (maybe 8th) nerve bundle that drapes across the side of the face, and its common in MS folks to have it flair up.
I find sometimes my teeth really hurt. not the teeth themselves, and its really hard to describe, its more like the jaw bone, but not the jaw bone. I often find my sx worse at night, or when I lay down. I dont know if its because its quiet and I have nothing else to think about or if the position of my spine triggers stuff.
let us know what happens. if its really bad, go to the walk in clinich Tri gem can be excruiating and you will need meds. oh joy! more meds.