I had unprotected sex about 5 days ago. I am unsure if this person was "clean" but if I had to guess I would say she was clean. I have masturbated probably 4-5 times since the experience with her. Today I awoke to see a small purple spot on my penis shaft near the base. The spot is pretty small, about the size of a pencil eraser. It is not raised and there are no bumps. The spot fades around the border, and it is also worth noting that the spot is located on a visible blood vessel. It is on the right side of the shaft near the base, and I am right handed.
There is no pain or itching associated with the spot. I have no abnormal discharge from my penis and urination is normal. Squeezing the location produces no pus/sebum and it does not feel as if there is any sort of tumor under the skin. I don't want to go to a doctor just yet, but I plan to monitor the area for a few days and see if any changes occur.
I have been looking for several hours online, and looked at hundreds of pictures of early STD symtpoms and my spot looks nothing like any of them. I am assuming and hoping it is a burst capillary or something. Could a professional please advise me on this situation and any possible treatment, or perhaps a surefire way to know it is not an STD and is a burst capillary.