Post Dermabrasion Scar Turned Black After Injecting With Celestone Chronodose? (photo)

I recently went through dermabrasion. 6 weeks after the operation, due to internet research resulting in my massaging the scar, it seemed raised and sore. I was told that i shouldn't have been pressing it and the doctor injected the scar with a Celestone Chronodose solution. This brought down the swelling a lot and I thought it was getting much better. Today, 9 days after the injections, the scar has turned suddenly black. What could this be? Should I be worried?

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