Sllloooow down. Take your time.

Only move as fast as you can being very sure of what you're doing.
When I do my grids, I'll often make the eyes, nose, and mouth areas half the size by splitting them with another line vertical and horizontal to give me better control of the tighter areas.
What do you think of the grid method so far?
I should have mentioned, use an HB pencil very lightly on your drawing surface so it'll easily come back up and won't indent the paper. Not sure what you used, it looks like you've gotten the grid back up, but just wanted to throw that in there.