I notice a blister on my penis about 5 and half weeks after having a one nighter. It only lasted a day and a half. The night before I noticed the blister. I had masterbated. The next day I noticed it on my penis on the base. It didn't hurt to me at all. It's healing and still not hurting. When it popped, it had yellow sticky stuck that came out. Could this be because of masterbating or could it be herpes. I had a penis to penis contact by rubbing. I didn't notice anything on the guys penis. I also went to the doctor to ask about it. She said it could be a possiblity for herpes or a ingrown hair. She didn't really answer my question. I did a blood test and a cultural viral. I am still waiting for the cultural viral results. It was only one bump or blister. Can anyone give me maybe a clear answer because blood work is not always accurate and not sure about it.