Burning and irritation inside the vagina a week after having sex. I put cortisone 10 down there

Can you burn the inside of your vagina? I had sex with a guy and noticed about a week later I was burning and irritated down there bad I was red as red could be, it did not burn when I peed tho. I put cortisone 10 down there for the itching and burning but it just made it burn worse, I took some left over uti med i had and it didnt help, so I used boric acid it help a little then  set in a bath tube full of Epsom salt and it seemed to help alot but now my vagina has little cuts on it and itches and when my pee hits them then burn a little. But I'm not near az irritated as I was it's been like this for a week now... any suggestions of what it could be or what I could do.? I honestly feel like i burnt my self up down there because when i tanned i ended up setting in the tanning bed to tan under my but to get those lines and set there for 20 mins i dont this 2 days in a roll the second day tho i set there for like 10 min befor laying down.