Hello, im a 18 year old male and i have only been in one relationship, and had sex with the person, just the other day i noticed a red spot underneath my penis, it is round doesn't hurt, and doesn't look like a ulcer, i masturbate at least twice a day very roughly, i use no lube at all, like i said this doest hurt at all only when i rub it, it does seem to look like a blood blister, or a broken blood vessel but it is very round almost like a perfect circle.. any suggestions, someone told me it could be syphyllis chancre but their is no way, i had sex a year ago, and this just popped up, i haven't had any sexual activity since that person a year ago.