Really good head, but you should try to work more on those two blue tubes on the both side i feel like you did them quickly and didin't rly added détails on it. And also the hair i feel like they are a part for the helmet and not under it or maybe it's just me idk :/.
But still really good job looks really cool, it's m'y favorite one atm.
White Parts Am Talking About
Also i think you should add more stuff or change the white parts. When i saw the flat i though that we won't see it but i just checked the 3D preview and i realized than we see it on the back, i feel like it's still a wip there, so you can maybe add some stuff there or change it, like we will be able to see the hair there, it's up to you ^^
White Parts Am Talking About
the reason I didn't add scratches or anything other than shadow is because I intend to keep that back plate clean looking. I also thought the hair could come out of there but it would look weird and it is gonna lost the purpose of the pressure-locked helmet.