I am male and 23 years old. I did masturbate while in college up to now, so about 5 years. I masturbated 3 weeks ago and noticed sores or blisters on my urethra by the opening of my penis. I went to the doctor and had a blood test and urine test done both which came back normal. I was told by two doctors that the blisters were due to my masturbation and it would heal on its own. They said the ejaculation caused irritation to the urethra. I know the urethra is a sensitive part to the body, but how long would it take the heal on its own? I wouldn't say they are blisters, more like bumps or sores. Is there anything I can do to help it heal? Should I be worried at all? Is it normal for the body to respond like this to irritation with these sores? I don't have any pain urinating and I don't have a sense of urgency to urine. The sores do hurt a little but they bug me more since I can feel them and it is discomforting. Thanks for the help.