Helmet headshot protection for face shot?

A level 1 or 2 Helmet visually does not protect the players face.

Does it always give Protection for headshots, no matter if hit in the face or somewhere else on the head where the Helmet does not cover it? Or only for the space where the helmet really covers the head?

Bonus question, does the neck also counts to headshots? (it is also visually not covered by helmets)