How Can Vaginal Blisters With Painful Urination Be Treated?

I recently was in the ocean in Mexico and was told the water was a lot saltier than the water in Florida. I also engaged in sexual activity and it was what you might consider rough and possibly harmful. I now have what seems to look like blisters on my vagina and on the sides of my vagina. It hurts to pee and when I touched around I felt a little ball. I didn t think it could be anything transmitted sexually because I ve only had one sexual partner my whole life and my partner was recently tested and came out negative. Any information or recommendations you give me will be very helpful!