His mask is imprinted on his skull.

She continues pulling off masks, each time the mask, and Spiderman's head, being slightly smaller.
At about the size of an apple, the masks are palpably damp. At the size of a plum, the liquid coating the masks is becoming viscous and taking on a brown/purple hue.
Removing the final pea sized mask reveals what looks like the end of an earthworm, she glimpses some features on its surface, a tiny human face distorted in pain? before Spiderman's body collapses dead.

Why the fuck did they leave "Spiderman" untranslated?

Oh, "Spiderman" sounds stupid when translated into your language? Well, it sounds stupid in English too, but we deal with it.