What Could Puss Filled Bump On Penis Be?

                                                                 i have gotten a bump on my penis that is fairly large about a half an inch and is filled with puss towards the bottom of my penis.first i got it on the right side,then i got one on the left side also a while later.now i got it on the right side again.im worried as to what this could be after reading about syphilis.please help.