red busted skin on vaginal area???

just recently me and my boyfriend had sex.
we used a condom and what not...
we did it for a while..and it began to get sort of painful...
we stopped for a while..and then we did it again later on.
it hurt somewhat then too!!!
then after that when i went to pee it stung a little bit when it touched my vaginal area...but i rly didnt think nothing of it because it's done that before when i get sore from intercourse.n i went to the doctor[previously] before we had sex and got an std check and they said i didnt have an std..i had a yeast infection..so i dont think its an std. and he couldnt have gav me anything bcuz he was a virgin b4 we did it.
anyways,it still stung a little bit so i looked at it today and i noticed that it was very red and there was 2 small areas that i would describe as
"broken skin" or somthing.it wasnt bumps or anything...but idk what it was but its kinda scary. i jus want some advice on it...i was thinkin maybe it was bcuz we did it for so long and it irritated me or something.idk.pleas giv ur opinion!!!