I recently had a ball slammed into face and my eye wont stop twitching, what could be wrong?

Trauma. Trauma to the eye has the potential to cause long term problems. The twitching is likely benign and will subside but you should have a thorough eye exam to make sure there was no other damage done.
Nothing. Probably one of the muscles in the lid got irritated from the trauma. If your vision is otherwise normal, dont worry- it will go away in few weeks at most.