I’m worried about what this may be, anyone have any ideas?

i have been with the same person for over 2 years and we split. i started seeing someone else for the past month and just this past weekend we had intercourse and he accidently came inside me and i did not clean myself until the next morning. Ever since then it has itched and burned when i urinate and its just an overall uncomfortable feeling when i sit, i feel like i need to itch myself. this was on saturday and its now thursday. The red dot is where it hurts towards the bottom of my vagina. Sorry the second picture is upside down. !image