[@Toots]

Let's keep it simple.  An unfolded arm is only going to be a few sheets of his arm.  If they get cut, or damaged, he gets damaged but the limb isnt cut off. 
He loses the sheets, sustaining an injury and weakening the limb. Some of the sheets torn represent damage but he loses some stability

Also.

https://vignette.wikia.nocookie.net/powerlisting/images/5/5b/JRZTT_Paper_Manipulation.gif/revision/latest?cb=20150513133424

Again I refer to the anime read or die.  Paper is also made of carbon, same things as diamonds, all that matters is bonds. Tearing one paper is easy.  Try tearing 30 at once.  That's still pretty thin but significantly harder.

https://www.theboxotruth.com/the-box-o-truth-31-the-books-o-truth/

If you want me to get scientific papers about how just 20 sheets of paper have been known to resist slicing of knives and can act as make shift armor, 7inches stops a bullet, or the tensile strength of paper adds exponentially per sheet layered.  But I'm trying to keep it simple.  He cant lift more than a typical athlete with it, adding in leverage and mechanical physics.

It's a stretchy power that's just for visual theme.