i think this head is done
don't try to add more things on a minimalistic head
adding that full metal seal thing just throws off that people are looking at
if you are planning to keep it, try to make it seem like an etching
i'd say red isn't a good color for it, and you should just go with black or a dark gray

my only problem with this head would be the nose
and that's just because it's too pointy imo