I have a red spot on my penis. Please see the following picture.


It is not raised and has come once before. It takes a long time to go away naturally. In the time frame of months. It does not hurt, does not puss, does not bleed, nothing. Just comes and is irritating to look at. Does anyone have any ideas of what this might be? I was worried that it was penile cancer (even though that is extremely rare).

Thanks for all your help in advance.