system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does wetting paper permanently disfigure it?

Can we somehow "iron" it back to normal?
gpt
Paper is made in a wet process that involves being pressed with giant steel rollers. Since paper is a natural fibre product, the fibres are of all different shapes and sizes. By the time paper is done and sheeted all the fibres have been compressed to a uniform thickness. 

When you accidentally get paper wet, the fibres swell and cause the paper to wrinkle/get wavy. The reason it stays damaged after it is dried is due to the different size fibres swelling at different rates. If you were to wet the whole sheet and put it through a series of hydraulic roller presses it's possible that it would be uniform again, however any print on the paper would be destroyed. It would also be difficult to process such a small piece of paper and not have it break apart.