That's what they always do in the movies, if the face is not shown in the same shot as the naked body you know it's a body double. You have to have at least one shot of the face and body together otherwise there's no way it's really her. It would be a waste of money to have an actress's real nude body without seeing her face. It either wasn't her or there was no point in it being her - accept it - wishing it's not gonna make it true.
It's her
That was all she was willing to show within such a short time frame. It would be dumb to just get butt naked in the first few weeks. I guess this way it's better for her. She didn't get naked enough, so people quit her, but if she got super naked really quickly people would've still quit her by now because they'd have already seen everything...