What happen when your girlfriend is mad at you?

Girls get mad. Everyone gets mad at one time or another. So you could leave her alone for a few days, and see what happens, or if it was a mistake that you made, do something to make it up to her. Write her a love poem, buy her a flower or some chocolate, do something romantic! Make her feel like you really do care about her, and talk it over to see what the matter was, and if there is something you can do to fix the problem, then fix it!