Mel Gibson's Baby Mama: He Beat Me Bad

Oksana Grigorieva -- the mother of Mel Gibson's eighth child -- claims the actor "beat her up badly" in January ... this according to sources familiar with the case.TMZ broke the story ... Oksana went to court on Monday and got a domestic violence restraining order against Gibson, requiring him to stay clear of her.The picture (above) shows Oksana leaving her lawyer's office yesterday.  Sources