My dad in his 70s has been using a CPAP machine for over 20 years. When viewing his head from the side he has an extremely noticable indent across his entire forehead about an inch above his eyebrow which he attributes to his CPAP strap. It is not just tissue, it has very obviously reshaped his actual skull. So on myself Im careful not to make it any tighter than it needs to be and to move the straps to slightly different spots each night.
