I Have Been Sexually Active For 10 Months Now, I've

I have been sexually active for 10 months now, I've recently been having rough sex and about two days later I realized that there is a ball of skin blocking my vagina hole feels like it's the same texture as inside of my vagina but I'm not sure what caused it, it doesn't hurt at all but it's harder for me to pee now and I have no idea what this is, I'm 18 ...please help