Bruising that won't go away after Juvederm injection. Will this ever go away?

Thank you for your question, and I am sorry to hear about your bruising after Juvederm.  At 4 weeks any skin pigmentation should have fully resolved, so I would recommend you see your Juvederm injector for an examination to try and diagnose the cause of the gray color.  It may require something as simple as warm compresses to bring additional blood flow to help clear the discoloration, or if it is due to something called the tyndall effect as a result of superficial placement of the filler, then hyaluronidase can be used to help clear it from the skin.  Hope that this helps. 

You may have some hemosiderin deposition or post inflammatory hyperpigmentation from the bruise. Your doctor should be able to tell what it is and recommend something to help it resolve more quickly. It will eventually resolve on its own as well.