We had our granite countertop installed today, the countertop wouldn't fit because apparently the wall is not even, so they had to cut thru the wall,.as you can see

the picture.

The installer says the open cuts in the wall will get sealed when they install the backsplash. I'm not exactly sure how. I'm concerned that the wall maynsweat thru and may end up with mold.

For the backsplash we are going to install glass tile.

Do any of think this may be a problem. Any suggestions on how to address this?