Swelling under eyes after tear trough fillers MONTHS later?

Volbella XC is a Hyaluronic-Acid based filler, which uses Vycross technology, (meaning it uses a mixture of Low and High Molecular weighed Hyaluronic-acid). Unfortunately, Volbella may attract excess water leaving the patient with unsatisfactory results when placed in soft tissue areas, such as the under eye. In my experience, it is best to discuss removing the product with your Board-Certified Dermatologist. He/she may dissolve the product with an enzyme known as, Hyaluronidase. Due to the vycross technology in Volbella several treatments may be needed.
Once the excess product has been dissolved it is recommend any remaining hollowness be injected with a Restylane-L or Belotero, which has less water absorption.

Thank you for your question. Yes - this is likely related to the filler. I suggest you have this filler dissolved as this issue is unlikely to resolve once it has become problematic. You amy want to consider fat grafting or PRP to this area instead of HA based filler.  Best of luck!