In Jason X, it was told that Jason has miraculous regeneration abilities.

Scientist/Researcher: His unique ability to regenerate lost and damaged tissue, I mean, it just, it just cries out for more research.

But later in the movie, when his mask is taken off, we see that he has a deformed face.

Then, why doesn't the regeneration power make his face like before?

In Jason X, it was told that Jason has miraculous regeneration abilities.

Scientist/Researcher: His unique ability to regenerate lost and damaged tissue, I mean, it just, it just cries out for more research.

But later in the movie, when his mask is taken off, we see that he has a deformed face.

Then, why doesn't the regeneration power make his face like before? Is it stated in other movies of Friday the 13th franchise? I have only watched Friday the 13th (1980) and this one.