A small fat pocket has reappeared under my eye. Why does this happen and will it need to be removed surgically?

After 17 years, there is a good chance you have some excess fat returning to your lower eyelids. This can be removed surgically, or if mild, may be camouflaged with filler injections.

The puffiness or eyelid bags that people see under the eyes are from 3 distinct fat pads around the eye. Over time, fat protrudes forward creating the fullness and bags that makes the eyes look tired and aged.  The lower eyelid blepharoplasty surgery removes the herniated fat from each of these fat pads to restore the smooth contour under the eye. During the surgery, not all the fat from the fat compartment is removed to avoid leaving the eyes hollow looking.  Over time, some people will see the remaining fat begin to herniate forward again as support weakens which can create a bulge under the eye.  This can be removed with another lower eyelid blepharoplasty to restore the smooth contour.  Sometimes fillers or fat transfer can help to camouflage this as well. 

Unfortunately cosmetic surgery of any type does not stop the aging process. Aging continues after surgery and it is possible for aging to continue forward with time. There are many options you can look at..revisional surgery, fillers, etc...

Lower eyelid surgery involving the fat does indeed usually last 10 or more years. The health of the skin deteriorates with age, and the septum structure of the eyelid can weaken allowing orbital/eyelid fat to become more prominent again. Also the facial tissues descend exacerbating the lower eyelid/cheek complex. Sometimes surgery is the answer, but we have great injectable fillers that can also improve the appearance sometimes without surgery.  An in-person consultation would help best to go over your options. Best regards.

no photos but generically the cause may be a small herniation of fat due to loss of support or thinning of the eyelid skin and muscle support structures.  if this is the case a conservative skin and possibly also muscle tightening may help.  Since the risk of lid retraction is greater from removing skin beneath the tarsal plate is higher in a secondary ( repeat ) lower lid blepharoplasty,  sometimes a lateral skin excision can be done in a crow,s foot crease, perhaps could improve this as when repaired this could create an upward pulling vector.  you could consider exploring for excess fat, but this may not yield any excess fat.

The remaining fat in the orbit can present years after blepharoplasty. Contributing factors may be thinning of the septum in the lower lids allowing the fat pad to come forward, and descent of the cheek fat pads which calls attention to the residual fat pads. Options include surgical excision (preferably transconjunctival), CO2 laser tightening of the skin, and/ or filler injections to volumize the tissue in the cheek. If your surgeon is still in practice, you could consult with him/her for advice. Best wishes.