The Accursed.

Elly is asked by a family friend to spend a few days looking after an elderly woman living in a remote cabin. She readily agrees thinking a short trip to the woods will be a nice escape. The cabin turns out to be anything but relaxing as Elly begins hallucinating in ways that blur reality with her dreams. As the visions take over, Elly realizes that she was lured there by a demonic presence hiding inside of the woman just waiting to break free.