I have a rather large pimple looking thing i noticed after i was masturbating and i used astroglide witch i have used before so i dont know if thats it but i have never had sex or any sexual interaction with a girl before so i dont think its an sti or std help please :-(
It's an ingrown hair, look closely and you should see a little hole, get tweezers and try to pull it, it should pop and squeeze all of it out