I'll look into that when I wake up, but for now, superglue seems to have done the job. I did a test on the bit that goes on my forehead, as it's less critical. It's holding a seal, though, as we speak.

I put on my CPAP mask to go to sleep a few minutes ago, and found that my fat orange tabby Duke had chewed on it a bit. He mostly chewed up the silicone bit that goes on my forehead, but there is one thin clean break in the soft silicone of the mask where it seals to my face. This is causing a leak,...