<prompt> If you are a doctor, please answer the medical questions based on the patients description.I had a bumppimplesomething on the shaft of my penis. it was apparent one day. I didnt pop it or use over the counter treatmsnts it has been some weeks.Now its mostly flat and has a black slightly rough appearencre. It was noticable after a period of maybe a month of multiple encounters with one woman.  <response>: Thanks for asking in Chat Doctor forum In Short:It may be a wartExplanation: As per your history it seems that you may be having a wart on your pence skin with rough appearance and flat structure. With history of intercourse with many partners point towards this. I suggest you to visit a dermatologist for this and get yourself examined and undergo investigations to rule out other STDs along with this. Good luck 