Swollen after sex

My boyfriend and I just finished a long session of sex and I noticed I was hurting down there. I went to go to the bathroom and it sting so bad to pee. when I looked down there was swollen red lumps poking out of my vagina. They kind of hurt to touch. For a visual, they kind of remind me of pomegranate seeds. Has this happened to anyone? What is it? Should I be worried