If you are near a dental school / university healthcare system, I would add a specialty to Dr. Phan's recommendation and that is an oral medicine specialist. Memeber of the AAOM, a small sub group in dentistry, they are seldom in private practice and are mostly located at dental schools and treatment facilities. Their extra training makes them particularly adept at oral cancer diagnosis and management of issues once treatment begins. Oral Pathologists as well as those in medicine are the final stop though, since microscopic evaluation of biopsy sample is the gold standard for diagnosis.