I googled paper mache masks...
I can't give a reliable answer, too much variability.
I figure papyrus comes in leafs, and that it's fibers make it unsuited to me molded directly to the face like a roman death mask....
If I was making one myself, found a old book or pamphlet, tearing up a few pages, I'd want it a few pages thick at least on each side of my face.
One layer would be a joke (but undoubtedly done often) to paint on and put on a face with an expectation that it would last.
Issue is, the painted portion has text beneath it. If it is a important text like this, you would want experts, such as that bible museum in Washington DC could afford, to figure it out.
Likewise if the person went crazy between each page with glue. I don't know how professional or standardize the mortuary field was for the common man in egypt was, so this may be up to considerable variation.
Another issue is, we're dealing with waste paper. We might get rough drafts or scribal school horrors (F- material) that we'll mistake for the originals or desired product. A text the obviously ended up in the hands of a pagan so short after it was written likely wasn't valued very much by it's owner, we're talking first or second generation drafts here of the gosple. I'm guessing that the early communal christians didn't think that much of preserving this particular piece. I mean, honestly, how many could they of actually of produced by then? A few dozen max? I think it likely was asub-quality copy chucked out.
But I'd like to have everyone see it too as well.