There are several corners in my home where the dog's or the gate for the dog's has slowly cracked the plaster on said corners. The previous owner used some type of metal secured to the dry wall and plastered over the corners. This causes about a 2 inch area that need's to be replastered in several areas throughout the house. Do I re-do the entire 3-4 ft. area or can I get away with just the areas that are really bad? A few inches here and there.