I had the shot twice. The first time my butt turned black and blue, and it lasted a while. I told my doctor about it when I went for the second shot. He told me that it was normal, and also about the dent and how it happens in some cases, but not all. I never noticed that I had one until last week. It is about the size of a golf ball, maybe a little bigger. I am so upset over this. I am just glad I am not alone in this situation. I am shocked at how many posts there are. I read somewhere where it is curable. They inject some kind of saline into the injection site. I am definitely going to ask about this, and I will NEVER get the shot again!! I'd rather take Allegra!! Good luck to you all :-)