That's why a proper VR headset wins over the various cheap "strap your iphone in" things. The comfort on the latest headsets (that are not cheap, granted) are orders of magnitude better.

Anything worn long enough is gonna leave a mark. Ask anyone on CPAP

True - but, the degree and type of mark will likely be different.

Is an HTC Vive considered "proper"? I used one for an hour last week and had a red mark on my face for most of dinner.

If this is the mark of the beast, I'll take it.