Well, that wasn't always his face... he wore that mask so much when he was younger that all of the skin on his face died, and the mask fused to his face guts, etc. Now he can't take it off even if he wanted to, cause he'd suffocate or something? I dunno.
Just take it from me kids... Don't let babies wear wrestling masks, wigs, or plastic bags on their heads. It never ends well.
iI'll bet you planned on reading this to gain an obscure revelation about something arbitrary... but no, there is never anything interesting in the fine print... other than big words