Hi, so I had sex on Friday- we didn't use protection or lube. The next day I noticed my vagina, mostly around the opening and on the inner part of my inner labia was really sore and almost swollen seeming. It hurts even more today and I'm wondering what the cause could be. There is no discharge or weird smell but I did notice a bit of blood in my underwear. Should I get some monistat or is it likely just an injury from him being too big for me? Should I be concerned about an STI? Would it show up that quickly with those symptoms? Thanks for your help!