Out of seemingly nowhere, I started to experience some slight discomfort (almost like a sore that forms after you bit your lip) up in front of my two front teeth - I mean way up there, at the place where the lip and gums connect. I had been drinking an energy drink. Within an hour, the entire top AND bottom of my mouth in that area where the lip meets the gum was slightly inflamed and had little sores break out. Can't seem to find any similar stories online to figure out what caused this!