I am a 20 yr old male and have had a recurring sore on the inside of my lip for about 3 weeks now. It is not a canker sore, and is not at all painful. It is more like a very small zit. It comes to a head, and I can pop it and puss comes out, but 2 or three days later it returns. I only noticed it because I felt it with my tongue. I was looking around on the internet and found all this stuff about mouth cancer and it scared the hell out of me. I chewed tobacco in high school off and on for about a year but havent for about a year.