A Mother's Secret

In the final fight, Brittany Underwood beats Melanie Nelson by giving her seven punches.

In the next to last scene, Rebecca/Margaret gives Sam a beating, including several blows to the face. In the last scene, presumably some time later, there's barely a mark on her face, light bruising on her right cheek. At the least, she should have black and blue marks at her eyes and possibly bleeding, a broken nose.