If the hair is completely shaved, it will be covered with a layer of hair in basically half to a month. It will be almost thick in about 2-3 months, but it still takes close to half a year to grow the hair. If the beautician is not skilled, it is easy to damage the dog's hair follicles when shaving with clippers, causing the dog's new hair to grow. The hair that comes out will lose its luster and be unhealthy. In severe cases, it may even stop hair from growing.