well spawn has a mask but when he opens his mouth the mask tears where his mouth is... kinda tears apart but with a liquid sense. but that would be kinda hard to incorporate that into the head.
evil eyes and evil smile are a must but the mask dont have to be there
i know if you take the mask out, it will just be eyes and a mouth and that is alright with me as long as it looks good. if you can put the mask in with an evil smile then props to you. i just dont have the time to do that.
what ever looks good