Injection of a steroid such as Kenalog is a great way to help reduce swelling following rhinoplasty surgery. When combined with 5-Flourouracil, it can also help soften and possibly reduce scar tissue that is present from other surgeries. However, I would not recommend using a steroid to reduce the appearance of a bone callus on the bridge. This is something that needs to be addressed by an experienced rhinoplasty surgeon. From here, I would recommend an in-person exam by board certified specialist. He/she will be able to address your needs and recommend some options for you. Thank you, and I wish you the best of luck!
Web reference: http://www.spaldingplasticsurgery.com/face/rhinoplasty/