Pimples or bumps behind wallpaper
We noticed these hard pimples underneath a window. Did some research and many said it was from water infiltrating and causing the glue to crystallize. We pulled the window and didn't see much evidence...
Forum Discussion
Really puzzled on how water is to blame.
I had the same problem in the same place.
A water hose left spraying on the window showed that mine actually came from above the window. Water follows paths that can fool anyone. But my exterior was aluminum which I believe has more places for water to leak.
Although the bumps are showing only in that spot, you may find more below the present line when you remove that panel.
If you can find the correct panel, I would cut it a little high and maybe raise the border just enough to cover but not high enough to be noticeable from the rest of the room.
