Personally I wouldn't worry about it. I find that my dog's hair (she's a poodle) grows sooooo fast that it would be a blessing if her fur was cut a little too short. Just joking.... I say that, because my husband and I do the grooming ourselves. I know when you pay a groomer it must be disturbing to not like the results. If we don't like the results we have only ourselves to blame. I don't know what you could use to encourage hair growth. I think time and patience is going to be all you have going for you on this.