Yes, I heard they do because cortisone is good for any type of scar reduction. I might not go for the shots though. Why don't you try to use a cream? The cream works wonderfully. It may take more time but it is less painful than those shots that you may take.
Cortisone shots will often help to reduce hypertrophic scars so that they lay more flatly against the skin and are less apparent. They're often the treatment of choice, but the best judge of whether they'll be good for your particular scar and situation is best made by a physician with experience in the area.
Cortisone shots work by reducing the inflammation in the injured area so that pain in the area is reduced, the recovery process is quickened, and the hypertrophic scars are reduced after a few number of injections.