So today I had sex for the first time in over 8 months. I was consensual but also unplanned and spur of the moment. So no condoms were used. I have the Nexplanon implant, so I'm good on birth control and feel confident on the pregnancy part of things, however, almost immediately afterwards, I started itching around the outside of my vaginal opening. I'm not sure exactly why this is. I don't feel like an STD or STI could've been spread, noticeable, and this uncomfortable after less than eight hours. But I'm not sure what else it could be. I also did pee afterwards, like you're supposed to, for avoiding UTIs. Does anybody have any thoughts on what's going on or what I could do to help the situation?