New here so don’t know if this has been covered but I discovered a way of avoiding rashes and sores – sleep naked, at least from the waist down. That allows the skin to dry out over night. Prtoect the sheet with a piece of plastic and sleep on a foled up beach towel, flannel sheet, or other soft, absorbent material. You may have to change it once in teh night. hang to dry and re-use a few times before washing. More elaborate options available, of course.