Even for Snoke I thought it was an oversight on their part. Cloning the injury of a subject is kinda ridiculous.
I’ve said this before, I’ll say it again, Palpatine’s deformed face IS his true appearance, the ‘Chancellor Palpatine’ look is a Sith mask, a cosmetic disguise to hide the fact that years of Dark Side corruption have taken a toll on his face. Why when he rejuvenated in TROS would he look like he does in the rest of the films and not like a normal person? Because that is his normal appearance.
His fight with Mace Windu exposed his true self.