Hi, I had unprotected sex early Wednesday morning and noticed a small purple circle on the head of my penis three days later (Saturday). The circle is not elevated, does not hurt, has the same texture/consistency as the rest of the head, and looks somewhat like a bruise. Is it possible for this to be an STD or perhaps a syphilis chancre (there is a syphilis outbreak in my area)? I also masturbated Wed, Th (2x), and Friday. Perhaps a popped blood vessel in the head (does that exist?)