I had a tonsil stone once (I think) A couple of days after it came out a bubble type thing formed on my tonsil. and has been there ever since (about 2 1/2 months) It lookes like a blister (even though its not) but the middle is sagged in a little( or you could say it's an indention I suppose) giving it a kind of donught shape. Does anyone have any ideas to what this could be? Should I be concerned.