Hi Welcome to the forum!!!
When my arm is in a flare, I will get some bruising around the wrist similar to what you are describing, it will start off very small and then get bigger - It almost looks as if I have been knocked with something on the wrist when I haven't! I am not sure if it is related to RSD, but I would deffinately speak to your doctor if you have any concerns/questions.
Sorry that I can't help you that much
Love and best wishes
Alison
xxx