based on that assumption, I would completely saturate the paper so that its very limber and very pliable.
Then apply liberally wall paper paste and if this is over a vinyl paper, use that special paste for vinyl.
On the seams, use the seam sealer and if that does not work elmers glue works great. The seams will roll if you did not totally saturate the paper with water.
The tear, sometimes when wet the paper will go back and you can squeegie it back to gether. You might get a safety pin and use the pin to gently move the edges back in order.
Now, if you have a spare roll and the existing paper has not aged or yellowed, we can show you how to patch the area with a new patch.
Remember saturate the paper to make it loose its memory.
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