I don't know whether it's approved for use with cpap masks but I applied my old standard Corn Huskers Lotion on my nose a few minutes before putting the mask on and again the next morning after washing up. The redness faded away in a couple of days. I still use the lotion when my nose tells me to.
I checked the ingredients but my high school chemistry degree is not up to understanding much of what is listed beyond water and glycerin. The advertising says "No Oils." I think it lists alcohol too. I understand and have used that before.
Try it at your own risk.