Swollen Utheral Opening

I had rough sex with my boyfriend. During forplay he was fingering me and then used a vibrator on me. So a little before we started the actual intercourse. We noticed blood stains on his d**** i thought it was my period. So after sex we looked at my vagina and noticed once i spreed my vagina opened inside we saw a red stain on a little what looked like a ball & i think it is my utheral opening. Now i'm feeling discomfort when i walk or sit. No blood coming out, no pus, and not serious pain just some discomfort when i walk it sit. Had this happened to anyone? If so what caused this and how to cure or make discomfort go away?