You should go to the hospital and have them take pictures of it. At least. Even if you refuse to go to the police, at least you'll have proof that he has harmed you in the past. If he does it again. You say he's your ex. Are you through with him,? have you broken up and gotten back together, after he's hurt you?
Are you living at home? Can you talk to your parents?
First off, don't talk. It will further damage your voice while you are healing.
Have you been seen by your doctor? You will want to take pictures of your injuries before they fade in case you decide to press charges.