The problem with an entirely tilted bed is that your whole body will slide down, and will tug against your back skin. That's why hospital beds have the leg part come up so that your butt can push up against the sliding motion.
I put this at the foot of my entirely tilted bed so that my legs and butt are lying flat. This solved the issue for me. https://www.amazon.com/dp/B01BVXPU2C?psc=1&ref=ppx\_yo2ov\_dt\_b\_product\_details
I'm pretty happy with this one
InteVision Extra Large Bed Wedge Pillow (33 x 30.5 x 12 inch) and Headrest Pillow in One Package - Helps Relief from Acid Reflux, Post Surgery, Snoring - Egyptian Cotton Cover - 2 inch Memory Foam Top https://smile.amazon.com/dp/B01BVXPU2C/ref=cm_sw_r_apan_glt_i_81J9H4Z0RGGH67JRVNTD?_encoding=UTF8&psc=1
https://smile.amazon.com/dp/B01BVXPU2C
This one. (I have no affiliation)