3 weeks post Voluma in cheek hollows... bruising or Tyndall Effect? Please advise. (Photos)

Thank you for sharing your question and photographs.  Based on initial appearance the cheek hollow appears to be bruising that should resolve with time.  I would verify this with your injector to make sure that dissolving the material is not in your best interested, both from color and contour.  Hope this helps.

The Tyndall effect usually causes a bluish discoloration of the skin which is caused by fluid accumulation just under the skin because fillers can attract water and cause swelling.  Thus, the bluish discoloration is usually also associated with swelling (which can give the appearance of bluish "bags" under the eyes).  Based on the appearance of the photo, most likely what you are experiencing is prolonged bruising, which can, in some people, take weeks to months to resolve.  Close follow with your injector can help determine the appropriate course of care.  There are some laser treatments that can help speed the resolution of the bruise as well as oral or topical medications.  Best of luck!

It is hard to tell from the photos if that is bruising or not but I would suspect that's the most likely culprit, some vessel abruption during injection. Did this just appear or has it been there? Is it tender or touch or lumpy? I would advise you to have a followup appointment with your doctor to make sure your post treatment is going as expected.