Hi, justej, Old age: it's not just that's its one damn thing after another, it everything damn thing, all the time, at once. (Not you old, me waaaay old.)
Had ocassion to read up on Pressure Ulcers, a few months ago. (Us laypeople call them bedsores). That why they turn Covid cases in the ICU - besides that business of putting them on their stomach to breath better. There is an advisory board on them, and a classification scale, 1-4, 4 is worst.
Is this related? I was surprised to find out that sheepskin is one of the most effective preventatives, as a padding (apparently), aside from those mattresses that have air-bladders that shift the pressure around.
One assumes they must be sterilized before use. I didn't find out if the lanolin is removed. The person I talked to had lost his sense of smell - lost considerable interest in the world, for the time being.
I know those of us who have had a Total Knee Replacement have damaged circulation. My leg looks & feels like hell, anyway. The diabetes compounds that.
For goodness sake, take care of yourself.