facial swelling?

I have a full face mask. When I wake up in the morning I don't even recognize myself in the mirror because my face is so swollen. It goes away within an hour so I look like I'm human when I leave the house. My machine doesn't have a card reader so I don't know if there are leaks from the mask during the night. Any wisdom out there? I'm tired of looking like an alien.

Are you perhaps tightening the mask too much?
Is it all over your face, or just the part under the mask?
Have you washed the mask since you got it? It might be an allergic reaction to the stuff it's packaged in.
Are you allergic to latex or rubber?