inner labia swelling and itching?

I'm a virgin and haven't had any sexual contact for awhile, so I know this isn't an STD or result of sexual things. I was itching something fierce down there though, and had felt vaguely sore around my actual vaginal hole for about a day or so. I was going into the kitchen for something when I noticed that something felt strange when I was walking. I checked, and my inner right labia was swollen pretty bad. It wasn't painful, it didn't itch, it's just swollen. I tried a cold compress but that didn't do anything. I went to sleep for awhile, and the swelling has gone down a little bit, but not all the way. It still isn't painful, and there isn't any burning when I urinate, and there's no strange discharge. It's not itching or sore anymore either. I don't want to go to a gyno, as I'm not on health insurance at the moment. What could it be?