Hi.. I Am A Male... I Have A Problem Near

Hi.. I am a male... I have a problem near my genitals for a couple of months now.. I keep on getting a black bulgy spots around my penis. It disappears after few days but still reappears in a different place on penis. It sometimes pains a bit, when my penis is erect. But when my penis is not erect, these spots doesn't bother me. What could be the problem? It is confusing me a lot