I thought I would post this for future health anxiety sufferers. I had something very similar, if it is in line with your teeth i.e biting then it is almost certain to be a traumatic ulcer, expecially if you grind your teeth at night and or have lesions inside of cheek due to chewing your cheeks. Mine went down on its own but my dentist said they can stay there for ever or even increase in size if they keep getting knocked around.