After sex my skin gets irritated?

I’m visiting my boyfriend at school and we’ve had sex twice but it hurts, and we obviously want to keep going since we only see either other twice a month. Is there any kind of cream or something to not let it get irritated? Or fix it? I have sensitive skin so we don’t use lube and no condoms. we’ve never had any reason to. My GYNO asked me last time if I get irritated but she didn’t seemed concerned.