Initially I found that I could use it for three or four to as many as six or seven nights in a row, then I would develop lesions inside my nostrils, at about the 10:30 and 1:30 position. Occasionally I would even find a tiny amount of blood. At that point I would go back to my Mirage Vista for a few nights until the lesions cleared up. As soon as possible I would return to the Pilairo, because it is so comfortable compared to anything else.
Later I had a discussion with my respiratory therapist. He uses a *PAP also, and reported to me that he had started using the Pilairo as well. And he had exactly the same problem as I did. He said that he can avoid the lesions if he washes the mask religiously at least every other day.
I considered his solution, but I found that if I use a tiny amount of Lansinoh cream before I go to bed I eliminate the lesions completely. I've been doing that for about four weeks now, and not a single lesion since I started.
I cannot figure out how the Pilairo could possibly be causing lesions. The silicone is so thin and wispy that it amazes me that it could damage skin. Yet it does for some people. You can find other reports like this on the net. If this is a problem for you, I hope one of the solutions I mentioned will eliminate it.