Bethany
I do not have oral cancer but thought I did last summer. It was very scary. I went to my GP who didn't even see what I was talking about. I went to my dentist who thought it looked like an amalgam tattoo (mine was on the inside of my gum below my molar, close to the floor of my mouth). I went to my ENT who told me I had bad sinuses (helpful, but irrelevant). I finally went to an oral surgeon who told me it looked like an amalgam tattoo but it could be oral melanoma but more importantly, that anything suspicious in the mouth needs to come out if it doesn't go away on its own.
He did the biopsy. Yeah, it hurt as that's a spot where needles don't feel so hot going in. Moreover, the 5 days afterward were damn painful - he removed a fairly good size chunk of the surrounding tissue and swallowing was really no fun. But at least I knew what it was (an amalgam tattoo) and he knew what it was and I was no worse for the wear.
Not having had oral cancer, I cannot advise your next move. But I think you're getting really solid advice from some very experienced and very smart people on this site. I'm sorry their advice conflicts with what your ENT says but worst case scenario, if you have it biopsied and it is benign and is the inflammatory process he says, you too will be no worse for the wear, right?