Character Mesh Strange Warping

See the yellow denser part near the middle of the forehead? My guess is there is some handle there with a tag on it that should not be there. I notice you had quite a few handles around the place (due to the numbers like 2 and 3 in the rigging hierarchy). If you tag those handles, you can end up with things getting "stuck". I would look for any origins markers on handles around where the yellow part of the mesh on the forehead is not moving - you need to look through the relevant layers by hand. Then think about whether those handles are needed (delete anything not needed). It is generally better to tag origins for layers or similar - avoid excessive handles (because they can cause problems like this one).