My 14 year old daughter complained last night that her eye was bothering her. Last year she had a bad sty and I thought maybe she was getting another so I used the drops that were prescribed at that time. This morning she woke up with a black eye as if she had been punched. It was purple and puffy. I had her put and ice pack on it and within thirty to forty minutes, the purple color was almost gone. By the time we got to school, about another thirty minutes, it was completely gone. She said it turned a little purple later on during the day, and then went away again. At the moment it just looks a little puffy, but not bruised as before. What could this be?