I was taking layers and layers, and more layers of wallpaper from my bathroom and whilst removing it have dug into the plaster behind. I was planning to paint the room but would need these fixed. Would a plasterer be able to skim over the areas (the damage is in relatively small areas on various parts of the wall) or could I use a filler and sand it? Don't really want to waste a plasterers time if it is a small job. Thanks in advance.