Mysterious Injury & Sores

[Molly&Lilly]

Hello,

I need some help. We noticed about a week ago that my cat Molly's arm (or leg) was swollen, right below her elbow. It was about twice the size of her other one, but she was still bearing weight on it. She was hiding for a couple of days (which worried me) not really eating, and sleeping lots. But after that she was eating walking around and seem to get back to her usual self. Her arm was still a little swollen, but not nearly as bad. When we first noticed her injury we (my husband and I) examined it extreme close, looking for any wounds or any sign of what could've happened, and we found nothing. About 3 days ago we noticed that she had a wound on the inside of her arm, but it was scabbed over. Now she has a gash on the outside of her arm that she won't stop licking, and I know that wasn't there before. I live in a very small town, and there is no vet open this weekend, probably the closest is about 3 hours away. I pretty sure she has created this gash and I don't understand why, and I am wondering if there is anything I can do to help her until I can get her to a vet.