I have a problem with biting my skin, and recently i bit through the inside of my mouth (just below my lip) I bit through a sensitive area and bit out a sensitive chunk of flesh thats kind of round, has a red vein going through it and a little vein tail (that i bit off to take it out) It leaves me with a small but deep hole inside my mouth, but always heals up no problem I've been having problems with biting those specific pieces out since i was about 9. I want to know what it actually is.