Hi I am sorry about your pain. I don't have it in the mouth but I believe from others and myself with it in areas not just in the limbs it can go anywhere. I probably have it in my eyes and it took going to 10 eye specialists,neuro,etc plus 50 apts in a year to figure that out. I have rsd in my legs and now maybe in the neck/back. Now I have seen many rsd specialists even top ones like at Cleveland Clinic seem to brush off areas of rsd not in the limb. I do feel and of course I am not a doctor but a treatment that can help the limbs could help other rsd areas like organs,mouth etc.
Hope the neurontin helps. Give it time because it can take a high dose or a combo of meds as well.
As for doctors compassion I cant tell you how many times I have left crying from the lack of it. I try to just regroup,vent to someone,and then move on. It is hard but I have started to learn that I can't handle more on top of the already in terms of stress etc.
Hang in there