What is happening?

Okay so, something weird is going on. I noticed I had very faint burning sensation while I urinated. I wouldn't be able to tell unless I was really paying attention. I decided to look down there to see the skin around my vagina lol opening had puffed up pretty bad. I put a cold towel on it and the swelling decreased significantly. A couple days later I look back down there and it's puffy again. I still have a normal amount of discharge, no weird/stinky odor, nothing. And it's not the first time I've had a slight burning sensation. I got it before I was sexually active. But this is the first time I looked down there and saw that. Any ideas what it could be? Lol sorry for the book I wrote.