Trivia: When the Marines are suiting up to go hunt Jason, one of them asks "Who has the B.F.G.?", a blatant reference to graphically violent PC games "Quake" (1996) and "Doom" (1993) where the B.F.G. is the most powerful weapon available (the name stands for "Big F***ing Gun"). (00:38:00)
Trivia: When Brodsky is outside the spaceship, he is dressed like Dave from "2001: A Space Odyssey (1968)" (01:16:10)
Trivia: In the scene where Jason kills the two people in the Virtual Reality game, the guy with a goatee and shaved head is the movie's writer. (00:37:10)
Trivia: Famed movie director David Cronenberg has a cameo as Wimmer, a higher-up at the Crystal Lake Research Facility at the start of the film. (He's the man who gives the speech about Jason's regenerative capabilities and is later speared through the back.) He agreed to appear in the film as a favor to the director, who had previously worked with him as a special effects artist on his movie "eXistenZ."
Answer: Jason wasn't deformed as a child. Jason was deformed at birth. His regeneration can't fix anything better then it already was, just to where it was to begin with, therefore since his face was always deformed it can't be fixed better than its deformed state. If half his head is blown up it will regenerate, but only as far as the deformed state.
oddy knocky