the pfizer jab probably (intentionally) stirs up all sorts of auto-immune responses
shingles lay dormant then was triggered by the vax would be my guess
"Experts in Israel found that patients with certain autoimmune diseases who received the Pfizer/BioNTech jab were more likely to develop the rash than those without the condition."
https://www.the-sun.com/news/2744100/shingles-new-rare-side-effect-covid-vaccine/