I recently tried to touch up a spot on my living room wall. Nearly 20 hours later, that spot looks exactly like it did when I first painted it. I have the exact paint that the wall was painted with. Should I water down the paint a little to help it match? Would painting again with the watered down solution even help? I absolutely cannot repaint the whole wall, but hope there is a way to fix this. Will rolling over this spot with a roller brush instead of a regular paint brush make a difference?