Why is my forearm swelling after scratching?

I woke up the other morning and it looked like I had scratched my arm pretty hard while I was asleep because there were red scratches (I actually took some skin off) on my forearm. Now I have scrape marks, its red and swollen. It isn't warm and doesn't itch anymore, but hurts a little like its sore. Is this normal? How can I heal it quicker? Please help, thank you!