I had got a cortizone shot ( 4 to 5 weeks ago) in my wrist because it had become inflamed. The bone had begun to pertrude at the base of my wrist and thumb . The inflamation and pain has gone, however, the pigmentation of that area 3.5 long X 1 1.4 wide. It starts just at the bone where injection was administered, and continues midway up the thumb. Is this natural, or is this something I need to be concerned about. I just noticed it today, and if it had been my right hand I would have no concern but it is the left hand and that hand stays in the sun while driving.