hi. I recently had sex with a new partner, and it turns out that just after we had sex he developed a small reddish/purple "bruise" or "spot" that is slightly raised. He said it feels uncomfortable and he is conscious of it during the day. He went to the doctor, and the doctor said it was probably mechanical and should go away, but a week later the bruise and raised area have not gone down at all. What would cause a symptom like that? Is there an STD or infection visible immediately or within a couple of hours of having sex? Could it be an irritation to a condom?