My boyfriend developed an open sore on his penis after the first time we had sex a year ago. It was not a blister, but looks like a small spot where the skin simply came off. He got tested, and it is not an STD. He told me today that for the last 8 months, he develops small bumps on his penis that are not blister like, but are painful, about 4 days after we have sex. He said it is not after every time, so I am going crazy trying to figure out what this can be!! Please help!!