system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do hard candies make the inside of your cheek rough?

Squirrel away a life-saver candy for a few minutes and suddenly I've a ring of roughness.
gpt
The sugar is concentrated so it causes your cheek cells to dry out, making them less soft and more textured. It's the same thing that happens with any salty or sweet solution that is more concentrated than the liquid in the cells - it loses water to try to balance it out. The opposite happens when you soak in a bath of regular water (*less salty or sugary than your cells) and can get wrinkly - cells gain water and expand. 

This is also why you might notice you're thirsty after eating a bowl of ice cream or cake. You lost some water in balancing out all of that sugar.