Spinal tattoo questions

Hi there!

I have a rib tattoo that has needed 3 appointments to fix (1 line, 1 color, 1 touch-up). I am used to chronic pain and I'd say it was about a 7-8/10 on the pain scale each time.

I was interested in getting a spinal tattoo, but I was curious as to how much more it will hurt. My plan is to have my thoracic spinal cord traced with various plants spreading out. My questions are:

1. How much more does a spinal tattoo hurt over a rib tattoo? 2. Is the aftercare different compared to other tattoos if you sleep on your back?

Thank you so much in advance!