You need to first teach this baby to drop his head for you first...
1) cradle his head right arm over his head/neck, left hand over bridge of his nose.
2) Lightly press with your fingers to his poll...don't dig in, just lightly press...
3) as soon as he relaxes his head downwards even a half a centimeter release both hands and praise him with petting and a treat if you'd like
4) repeat steps 1-3 several times each session; DO NOT release pressure til he "gives" to it.
Another thing, if he is so scared of your hands near his face, you may want to spend some time getting him used to you rubbing on his neck, head, and face, before attempting to teach him to lower his head...it does no good to try to teach him how to lower his head if he is terrified of your arms being there in the first place; get him used to you being all over him, THEN start teaching him to respect such wishes as giving to pressure.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."