real sore at the entrence of my vagina

This definitly sounds like a UTI..urinary tract infection. You should go to the hospitals emergency room and have them look at you, or go to a gyno because UTI don't just go away...and can become very very serious if untreated...untreated it can effect the kidneys and possibly be fatal...otherwise it's just a simple trip to the hospital and they will start you on anti biotics and vwalla! it'll be gone hope i helped, if any other symptoms occured lemme kno, but im sure this is a UTI...you need to go to the doctors