Caroline--I hope that your symptoms turn out to be something less scary and dangerous than you have been fearing. I hope you will also go beyond the docs you have seen so far and include a good ENT in the mix, as others have suggested; I think they are best for ruling in or out the possibility of the cancer you have feared, and be best able to give you peace of mind. A thorough exam for oral cancer is not that difficult; scoping the base of the tongue with a tiny tube causes some tickling and slight irritation, but it is brief and the only way to see the hidden parts of your oral cavity. A PET scan can help identify any indications of cancer anywhere in the body should there be any visible indications of cancer. Whether the news is good or bad, getting the news as soon as feasible, and with the highest degree of certainty, will be the best solution to your health anxieties. Good luck!