I called the police and they deemed it mutual combat (which is typical in California), but I had pictures taken, went to the doctor, then went after him with a restraining order and got it.
In fact, they made it permanent (3 years is the max in California), and it bars him from having contact with my kids. He really blew it by showing up in court and yelling at the judge. What a winner!
Take notes on EVERYTHING. Get a journal with numbered pages that cannot be removed and write in it daily. It is your best defense/offense.