Not a headshaker as such, but definite trigeminal neuralgia. Carbamazepine (tegretol) was completely ineffective at normal and and only slightly effective double dose. But it's 'relatively' cheap and there isn't any good reason not to try it. Mine had a seizure the night before the knacker man was booked. I hope yours has a better outcome.
So sorry you are needing to look at going down this route.