OK: the front plane of the face is good. Nice loops around the mouth and eyes.
The side planes and the skull need some work. Make a copy and delete everything behind the front plane (save as first, work on the copy.)
Select the edge loop on the forehead marked in yellow (remember, everything behind this loop is gone.) In side view, extrude, grab and move it back some, and rotate it. You should get new faces shown in light green. Move to front view and fan the edges out some, so they are not all vertical. Back to side view, extrude, move and rotate again, you get more faces shown in dark green. Adjust the edges as you go, to get a nice rounded skull shape. Google Grey’s Anatomy, the wikibook has some great references if you want a realistic skull.
Keep doing this extrude, move and rotate four or five more times (see blue lines) until you have the hard part of the skull done. (By “hard” I mean bone, not difficult.)
Finally, you need a loop to define the jaw: that one is shown in red. It’s a continuation of the forehead loop, runs in front of the ear opening and then along the jaw line to the chin. (Underneath the chin, actually, you don’t want to disturb any of the good loops you’ve got around the mouth.)
Beneath the jaw and the skull lies the neck, a very complicated bit of business, with windpipes and long muscles and tendons connecting various parts of the skull to various parts of the upper torso and shoulder anatomy. I’m not going to get into that now. But I would suggest looking at some reference photos of people with their heads in extreme positions, to better understand how and where the neck shapes are connected.