How do you know if you're allergic to semen?

My vagina never irritates me more than when my bf cums inside of me it's just a burning sensation it burns when I pee, it's a hard feeling to get over I even think it swells a little bit & is red like a rash, it will go away overnight but I can still feel the sensation a tiny bit the next day this only happens when his semen comes in contact with my vagjna