I had a block done a few years ago. I'm not sure if it was this specific one or not. It was pretty easy, I didn't have any problems. But I didn't notice any pain relief, either.
"For this thing I besought the Lord thrice that it depart from me. He said, My grace is sufficient for thee: for my strength is made perfect in weakness. Most gladly therefore will I rather glory in my infirmities; I take pleasure in infirmities, reproaches, necessities, persecutions, distresses, for when I am weak, then am I strong" 2 Cor