So I have had a worry for about 7-8 months ago with a sexual partner we have had oral sex and regular sex currently not sexual active. But during that time period i had a pimple that showed up a few centimeters below the head of my penis. With a red base and it hurt when i would masturbate. It doesn’t sound like any other STD besides syphilis it kind of resembles it but not sure. With my knowledge i know syphilis is painless but it was durable painful for me. And it went away within 2 weeks i believe. If anyone can share some information it would be appreciated thank you.