We have popcorn ceilings with a few dark spots and one spot where we had to cut part of the ceiling out. I am having trouble getting clear directions on how to repair stains on popcorn ceilings and how to blend the repaired hole into the rest of the existing popcorn texture. Taking the popcorn texture off completely is not an option. Pieces were falling in chunks when we applied popcorn ceiling patch to the edges of the patch. The current ceiling has also aged and is not a true white anymore. Please help.