Mysterious Bump

This bump has been on my vagina lips for awhile now and it generally doesn't hurt unless my underwear or jeans rub or pinch it the wrong way. Any idea what it could be?

Also it's very unlikely that it's a genital wart or a sexually transmitted disease because I've only slept with one person ever and it was with my boyfriend and we both are clean.

UPDATE!!!!! It went away on its own after about a few weeks. Thank y'all so much for the help