Why won't bruises on my leg go away?

Last July 4th, almost a year ago now, I was injured when a roman candle misfired & hit me in the right shin. Two places. There was only a little bleeding & the skin was tore up. The scabbing disappeared about 5 months ago, but the bruises are still there & look like they won't go away. I have never had anything like this happen. It usually takes a miracle for me to bruise & they never have lasted longer than a week. I do have congestive heart failure. I don't know if this can cause this to happen. I have been diagnosed for 5 years. I am in my lower 40's. I also have had a new thing with my finger nails growing much faster and thicker. I have been tested for diabetes. No problem there.. No yellowing of the nails. Just unbreakable. I wonder if these two things can be connected.

Thank you for any advice.