itchy vaginal opening

Okay so I recently had unprotected sex with a new guy that I had been talking to that claims to be clean and about 3 days later I'm having an itchy feeling on my vaginal opening only but it's not horribly itchy and I'm not sure if it could be from him or because I accidentally used the wrong soap on my vagina like the night before it started itching. And it's not itchy like all day.