I'm sorry this has happened to you. There is hope though.. dents caused by cortisone injections tend to fill in by themselve over the next 2-3 months.

I did many self treatments of saline injections. I know it's not safe but it was so cheap and painless to perform. But saline injections make your scars/dents look better for a few days but then after that your scars will look pretty much the same. Supposedly it's suppose to be like a mini subcision so maybe collagen may fill in over time but I wouldn't count on it.