It has been there as long as i remember i think i never remember looking at it and wondering where it came from but everytime i see it i get worried its really small a few shades darker than the skin and it isnt expanding or anything and i know it also has nothing to do with any STDs
Ill include a pic just so you know what it looks like
https://s.yimg.com/hd/answers/i/4e3856e3b9564127b2de0b2a8bc75f94_A.jpeg?a=answers&mr=0&x=1492428246&s=41ab9594061875c8d27e1a7a997856d9