Weird cortisone injection question

[Nonny]

I have a really bizarre/weird question about cortisone injections.

I had one on my wrist on Sept. 18th.  The injection site is kind of by the little knobby bit of bone on the wrist on the dorsal side.  It bruised at the time and had a mark for over a week.

Over the weekend I realized I had a red mark in the same spot. When I first saw it I thought I'd just rested my arm on something, but it's stuck around.  In addition to being red, the area is kind of dry and almost scaley or rashy looking, but it doesn't otherwise hurt or itch, it just looks weird.

It seems related since it's in the same spot as the injection, but is it?  Three+ weeks seems like a really delayed reaction if that's the case.

I see the doctor in another 1.5 weeks for a follow up, but I'm bored so I thought I'd ask here if anyone has had anything like this.  Googling "cortisone injection reaction" just results in people having major allergies right away, nothing quite like this.