Does cum burn in your mouth or is that just me?

My boyfriend and I have been together for a bit over 2 years and I didn't have much "experience" before dating him, so I'm not sure how unusual this is:

It used to be that if we were having sex or something and he finished somewhere on my skin, I'd get a burning sensation almost immediately and I'd feel it for a little while even after I washed up, and the skin would be a bit red and irritated.

Now I think I've gotten used to it on my skin (it doesn't really burn there anymore) but it's still a problem if it gets in my mouth. One of the reasons I hate the idea of swallowing is cause I'm worried about how bad it'll burn when it goes down. I don't think my throat would close up but it definitely wouldn't be comfortable.

Idk if my skin/body is just super sensitive, or if this is a thing that happens to other people. I'm not super worried about being able to swallow, cause honestly I don't mind having a good excuse not to 😂😂

I'm just curious if anyone else has had these issues and if so, how did you deal with them?