I Have An Itchy Cheek. It Is Almost 2 Years

I have an itchy cheek. It is almost 2 years that my inside cheek itches. I feel there is something there, I can touch and feel it with my fingers. My dentist checked that and said it is nothing serious. But it is annoying me alot. It annoys me at 3 occasions specially 1- whenever I do not eat food for a long time, 2-or whenever I exercise or 3- whenever I eat fatty food . What do you think it is?Do you suggest a biopsy?