Some patients have a hollowness under their lower eyelids which is commonly termed a tear trough deformity. This is caused my several different issues, it can be due to excess skin, protruding fat or loss of volume which occurs as we age. This needs to be correctly diagnosed before a treatment plan can be formulated. Lots of people think that an injectable such as Restylane or Juvederm can simply be injected into this area for correction. Sometimes that is helpful (in the right candidate), but if there is an excess of fat in the area, an injectable can actually worsen the appearance. Usually a lower blepharoplasty (lower eyelid surgery) is needed, and not just a simple injection.
This is an area that a board certified plastic surgeon can help you diagnose and treat, whether it's with a surgical or non-surgical approach.
Best wishes,
Dr.Bruno