Jonathan,
It would seem like a good idea to try to get to see an ENT that has some experience with oral cancer. I'm not saying this because I think that you have it, but this particular ENT's manner doesn't appear to be someone I would trust. I have heard of way too many dentists and physicians that have blown off poeple that did have cancer with an attitude like his.
And, besides, the sooner you find out, hopefully that you don't have cancer, you will be able to get back to living a normal life. And, if it does turn out to be something, treatment started sooner rather than later, is imperative.