The process in which a snake sheds its old skin is called ecdysis.
A snake’s outer skin does not grow continuously with the body, so the animal periodically forms a new layer beneath the old one. Fluid can collect between the layers, making the eyes look cloudy and the colors appear dull shortly before shedding. The old skin is then loosened and rubbed against rough surfaces.
Ecdysis usually removes the outer layer in one connected piece, although it can tear if conditions are poor. Young snakes generally shed more often than adults because they grow faster. Temperature, food supply, health, and species all influence the timing.
Shedding is not the same as regeneration: the snake is replacing its external skin, not regrowing a lost body part. The discarded skin is called an exuvia. Snakes may be more vulnerable during this period because cloudy vision can reduce their ability to detect threats, so many seek shelter until the process is complete.