system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does your skin 'dent in' when wearing e.g. a too tight wrist band or bra strap or rubber band?

What happens to the cells? What process allows them to bound back in place and is there any damages? Why does it get reddish?
gpt
There is water in three places in your body: in your blood, in your cells, and between your cells. There is an equilibrium between these three, and one of the large determinants of where that equilibrium sits is physical ("hydrostatic") pressure. When you compress the tissue for a while, you increase the pressure and force some of the cellular and tissue fluids into the blood to be carried off, leaving a dent. When you take the pressure away, the fluid comes back to restore the normal balance.