All of these things could be the result of something as common as a bacterial infection. You do not mention if you have any risk factors for OC. Do you smoke? Are you a heavy drinker? If you eliminate these, coupled with your youth, the odds of this being a malignancy is small. Since you have already seen an ENT, my suggestion is that you get a second ENT opinion, from one that has experience with head and neck cancers... most that do are surgeons and have seen it all. If you are near a dental school, I would go there and ask to see an oral medicine specialist as another highly trained possibility to obtain an informed opinion. You also could get your current docs to rule out infections by doing a blood test and check white cell counts. Differential diagnosis, is a combination of looking at risk factors a patient has for the disease, and the elimination of all the common mimics or other causes that share the same symptomology that it could be. So before you jump to the worst case, there is more to do to eliminate the simple (and not deadly) things it might be.