So as per the advice of a helpful comment-er and some internet research, apparently I am not drinking enough water, which could be exacerbating my back and skin issues. I decided to start last night, immediately regretted that. Drinking 500 mL water and going to bed apparently makes me get up every two hours, going to try a more balanced approach to that.
I also, by shear dumb luck, managed to identify something I was doing that was twisting and putting pressure on my lower back. So this may be real, and if I am right, will improve soon.