I'll add that most penile rashes and bumps are non-STD skin problems. Probably this isn't anything serious.
You don't provide enough information to judge the possible causes. It depends on how long the spots have been there, what they are like (painful? redness? growing?), whether you are circumcised, and exact location on your penis. Also whether you have been at risk for STD (new partner, multiple partners, etc). So at this point I can't even guess at the cause or the best treatment. You should see a doctor or clinic for professional evaluation.
Good luck!