The thing is that Part 1,2,3 and 4 versions of Jason head/face followed a concept design that Tom Savini created,but when part 6 came out,that concept design was kinda changed,same for part 7 and 8,then changed even more with part 9.
Only Jason X,Freddy VS Jason and 2009 Remake got back to something similar to the design made by Tom Savini.
If we follow Tom concept,Jason is supposed to have a deformed head shape wich is bigger than a normal head shape,a deformed derpy/sloppy right eye wich is a bit lower than his normal left eye,a deformed nose,deformed mouths with mishapen teeths and i think one of the ear is also deformed.
While it's true that zombie Jason (part 6,7,8 and 9) had all the damages he received from Part 2,3 and 4,his facial designs are not the same even tough it's decomposed.
To start off,Part 6,7 and 8 changed his right deformed eye into a normal eye making it like his left eye was his deformed eye all along,part 6,8 and 9 doesnt seem to have the right eye lower than the left eye except part 7 and the kid version in part 8.
The shape of the head on part 6,7 and 8 (except part 8 kid version and part 9) doesnt look deformed,it's true that his skin decomposed but the shape of the top part of his head skull should not be like a normal person.
For the nose and mouth,since part 6,7 and 8 doesnt have a nose it's impossible to know if it was originaly deformed,same thing for part 6 Jason mouth since the lower lip is falling down sideway a bit because of the decomposition and the teeths doesnt look mishapen,part 7 and 8 mouth on the other hand have mishapen teeths,so we have proof that Part 7 and 8 Jason had a deformed mouth with mishapen teeths.
Then finally there is part 9 wich somehow whoever made that 'look' decided to make the right eye the one that he is missing and added back his normal left eye as if he never received a machete on that one.