Chances are they won't come. If it was sooo important, she would have gone to he hospital, and they would have called the cops, of she would have called 911...she is yanking your chain...but if you get back together and something else pops off, she will use this time to show that there is a history or pattern of domestic abuse, and yes you will get locked up. Because, in the cop's eyes you are a woman beater.
She of course thrives on drama like this, so you only deal with the child. And you knew she was crazy before you had a child with her---before you bust a nut, make sure she ain't a nut.