The responses here echo my experience. It was tight at first but loosened up over time as I lost weight. They also made some cuts that made it more comfortable while still keeping me immobile.

I also was given Ativan even though I never really felt that anxious in the mask. The only caution I'd contribute is that there can be withdrawal issues with Ativan if you take it for a few months and then abruptly stop. I'm dealing with that right now and it's taking a gradual reduction in dosage to get me off without the side effects I felt when I went cold turkey right after treatment.