With my eyes I can't tell you how many rsd specialists said go to another eye doctor after 50 apts of them and 10 specialists or blew off the eye pain. This was with pain doctors who deal with rsd at Cleveland Clinic. I understand your frustration with that in regards to your mouth. I finally came to the conclusion and this could be very wrong but that if I could find pain control for the limbs it would in turn help with the eyes.
For me neuros more were about doing a lot of dx testing to rule out other conditions and then I was also dx with PN. They did a little with meds. I am sorry did you say what state you live in? Have you called a teaching university hospital in your area the pain dept/anestesolgy? I ask because that is how I found my best pain doctor better then at Cleveland Clinic and UCLA.
Hang in there and hope you feel better