What Causes Dryness And Peeling Of Skin At The Vagina?

Hi there, I recently had sex with my girlfriend and while I was using my fingers as foreplay I felt that her vagina felt rather dry. I ignored this and had intercourse with her. She checked and indeed it was dry and there was sunburn like peeling near her vagina. I woke up this morning (2days after intercourse) And noticed tons of skin peeling off my penis. It's almost like a sun burn and some areas which do not have this "Whiteish skin* are red. It's almost like a build up of smegma but instead of the sperm it's a build up of skin. I am capable of peeling it off, but I rather not, I have applied vaseline on it, just like she did near her region. Please help is this an STD or is it some kind of irritation. At certain times it itches for a tiny bit, but it rapidly goes away by itself