What Causes Swelling In The Labia Minora?

my labia minora hurts and was swollen, the swelling has gone down but it still hurts to touch, sit, stand and move. It's not itchy but it's VERY painful to pee. I looked at it and there looks to be a cut on the inside. I am on my period right now which makes the pain worse. I need to pee very badly but can't because of the stinging pain is to painful.