16 years old , pimple on vagina

well im 16 years old.and im really worried.Just yesterday i noticed i had a pimple like on my vagina.it's not in the inside, it's on the outside. I've been with two guys only, but i've had my boyfriend who im currently with for the past 3 years. I've never felt or had anything down there except one time which i thought it was because of the condoms we use, and after changing to others everything was fine. So this is what i think happen this time, i had intercourse with my boyfriend on Saturday, i remember not taking a shower that day,i've been exercising a lot and sweating way to much and i did take a shower after saturday, but i hadn't shave n when i did yesterday i saw the pimple like. It doesn't hurt, it doesn't itch and doesn't bother me, PLEASE HELP ME.I'm really worried.What could it be, can i or is it fine if i have sex, or do i wait until this goes away????or what can i do so it would dissapear?