has anyone had a persistent mouth ulcer? I don't usually get them but i've had this horrible sore one at the back of my mouth for over five weeks now. Terrified its something horrible, i don't smoke but i have done [for about a year] and i used to take inhalers for asthma [stupid combination yes i know]. Just can't get rid of it. Going back to doc next week just wondered if anyone had had a similar thing.