[pseudohadamard]

It's not even dementia, it's shingles itself. Two friends of mine had shingles in the last year or two, one of whom has a pain threshold at a level where I'm not entirely sure he's human ("I pulled the flesh back and you could see the bare bone, it was interesting, I've never seen my insides like that before"). After hearing their description of the pain levels involved I got a shot the next week.

My older neighbour also had it a few years ago, but in her case wasn't aware it was shingles, just some rash on her face. Doctors said if they hadn't stopped it within the next few days she'd have lost her sight.

Get the shot. You probably won't need it, but if you do then you'll really need it.