beware if you attempt to give blood with cpap mask rubbing

[sleepybones]

i've just been rejected from blood donation as my mask casued rubbing which broke the skin on the bridge of my nose last night - probably due to the high temperatures and me using a moisurising cream to moisturise it, and it looked like a small (size of ball bearing) spot. 
annoyed

[Mosquitobait]

Oh yeah, the open sores rule. I sympathize.

[chill]

Not to your original point, but have you considered that your mask may be too tight?  I can't image how mine might cause an open sore, despite heat, humidity or what I put on my skin (well, excepting strong acid).  They usually work better loose so that the silicone pad can inflate properly and seal.  This fact is not intuitive when you are having leaks.

[Marillion]

That's a very good point by chill and one I would agree with.

[KSMatthew]

Once or twice a year I'll get an irritated patch on the bridge of my nose. I suspect when I move while sleeping I sometimes get a fold or edge of the silicone skirt on my mask that rubs that area.

Rather than using cream or other lubricant, I use a paper medical tape. You can find it in any first-aid section of any pharmacy. It's made by several different manufacturers, and they generally have some made for "sensitive skin" or labeled something similar.

I'd include a link to an example, but sometimes that's frowned upon here.

Using scissors I cut a small section, maybe an inch long (about 30mm) and then another thinner section about 1/4 inch (about 5 mm) wide. I double-stick the thin section to the wide section, right in the center. That gives me a bandage with exposed adhesive on either end and a non-sticky surface in the center. I apply that bandage to the bridge of my nose - the adhesive is on the sides of my nose and the non-stick portion covers the irritated area. The mask seal still works fine and the mask can rub against the tape instead of your skin. After a night or two everything is fine again. One roll of that tape has lasted me for years. The dimensions I gave are just a guess to give an idea of what I do. You can experiment with whatever size fits for you.

[pholynyk]

Good idea, and your conversion factor is off by 10... the long tape should be 30 mm and the short one 5 (or 6) mm.

Just in case, for the Europeans and Canadians who are unsure of US units

[KSMatthew]

Good idea, and your conversion factor is off by 10... the long tape should be 30 mm and the short one 5 (or 6) mm.

Just in case, for the Europeans and Canadians who are unsure of US units

Yeah - I meant mm, typed cm.

That's why us Americans never went to the moon...wait...

[pholynyk]

Third   Seventh time's the charm...

Oops, NASA has landed people six times already, last time is December 1972...