Why does my undereye look hollow after Voluma?

Thank you for your question. It is important that Voluma is skillfully injected to create a natural and more attractive appearance. Return to your injector and discuss your concerns. Best, 

The injection of
Voluma, as with all fillers, needs to be done in an office of a board-certified
dermatologist or plastic surgeon as they best understand the anatomy of the
areas that we are injecting, the precise placement of the filler, and how to
best use these in your cheeks/mid-face and in all areas of the face. On
occasion, the problem you are describing does happen, even with skilled
injectors. It is why we routinely speak with our patients after the procedure
to make sure that they are doing well, and let them know if they have any
concerns, such as what you have, that we get them into the office and address the
concern with them. You may need a little more filler to correct the problem –
usually Juvéderm, Restylane, or Belotero will work well here as a touch up. I
would go back to your injector and find out what he or she recommends and let
them take care of it, if they are skilled enough to do so.