What do skin "rolls" on a BP mean?

So, I just went to handle Pylox earlier, and I noticed that when he makes a "U" in any part of his body, there's some excess skin making curls. I just wanted to know what caused this, I personally don't think it's dehydration because the ambient humidity is usually around 63% and he never touches his waterbowl.
https://uploads.tapatalk-cdn.com/201...9e9a18795e.jpg

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Looks like it's nothing. Same thing happens to your neck when you turn your head.

he probably could use a meal! :)

though my 900g+ Yellow gets a few rolls like that, too:
https://ball-pythons.net/gallery/fil...8/yellow_1.jpg