As far as I can tell this is basically how it is in all three official continuities, with occasional exceptions like Dooku. Honestly, if you want him to look monstrous, giving him yellow Sith eyes would be a good start.
…yes… that was the point I was making… Dooku is an exception. There shouldn’t be exceptions. You don’t get to mess with the dark side without consequences.
And the Prequels made it so Palpatine’s face is because of the lightning. It should be dark side corruption.
Not only does Vader’s suit look monstrous, a result of his immolation, a cosmic consequence, but under the mask he’s pale and scarred because of the dark side. He’s canonically supposed to be 46 but looks far worse, a testament to how much the dark side corrupted him.
In my interpretation, Zabrak’s are naturally brown (like Eeth Koth and Agen Kolar), and Maul looks like that because of the dark side.
That just leaves Dooku, and I’ve already posted what I plan on doing with Dooku.