
That could be a couple different ones.
But, Inquisitor Gregor Eisenhorn had his ability to show emotion severed during interrogation by an enemy, and due to that person’s ineptitude at torture, he lost the connection for some nerves in his face. I’m reading that series now, having started several books too far into it and finding a ‘you’re the clone of other character from the first few books’ and needing to restart so I could get the full context

I am not far enough to know if it happens an additional time, or if he ever gets them repaired. In the book I read first (supposedly 7th in the series, by mistake) it seemed he could make some expressions but that takes place a while after the first book in the series that I’m wrapping up, where it has just recently taken place.
The first book is called Xenos, at least that’s where I’m reading that covered the paralysis part.