Damn, the "barbed wire" facehugger is such a nasty and raw addition.
Not only does it have acid as a defensive mechanism, but if some other party tries to remove the facehugger from the host by other means, it will start ripping off the skin (and more) from its victim's face, therefore making it more likely for it to be left alone.
I wouldn't be surprised if this is Isabella's disgusting scene.
She gets face-hugged, and when the other crew members try to remove it, the facehugger will rip her face her off.
Knowing Fede and his movies, this could probably be his best practical effect achievement yet.
Evil Dead had the arm scene, but this seems like it could top it.