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.
I use Sudocrem it is both a barrier cream and anti septic. I rub it in well and have never (touch wood) had a rash since I started using it. It can be expensive and I get mine from a big American Cash and Carry.
I also use talcum powder on top if I am going out as it helps the barrier last longer. This works for me.
The good thing is that with nappy changes between showers, cleansing wipes take away the talc and smell leaving the barrier cream. It is especially good when you are out. I just add more talc. Hope this helps