Need a cover up for a face to make it more horror-ish
Check out this video tutorial, might help: http://www.videocopilot.net/tutorials/demon_face_warp/

To summarize: You need to motion track the face and stabilize the footage with this tracking data. Good tracking points are the corners of the eyes, nose, etc (the new face tracker might help but I haven't used it much). Once your footage is stabilized you can apply whatever you want onto your actor's face. Then it is a matter of pre-composing everything and re-applying the motion to that precomposition.