I pioneered the definitive surgery for post-lower eyelid blepharoplasty retraction repair using a vertical midface lift, hard palate graft, and ePFTE orbital rim implant (see attached video). Others don't take this approach. They may use a lower eyelid spacer with some type of lateral canthal surgery. The choice of the spacer has a significant impact on the success fo these surgeries. The harvest of a hard palate graft is a extra surgical step that requires an acrylic stent to cover the roof of the mouth after removal of the graft material. This prevents bleeding at the harvest site and protects the area from trauma during the healing process, but requires the patient to see a dentist to have the appliance fabricated. Many surgeons find the harvest of the hard palate graft an unnecessary burden and use alternative graft materials. I have been doing these surgeries for 30 years. In my opinion, there is no other satisfactory graft material for a number of reasons. Alloderm is cadaveric dermis derived from deceased humans. The product is carefully processed to remove cells and irradiated to remove virus. It comes sterilized for surgical use. It is basically a patch of human collagen. The challenge with its use in the lower eyelid as a spacer, is that it can cause chronic inflammation, which is what you are describing. Even then this reaction does not occur, the body seems to remove the Alloderm material over the course of several months. Surgery that relies on this disappearing graft tend to fail. You sited the post of another who received a porcine graft material which presented with chronic swelling of the lower eyelids. I have managed patients with this issue. Generally the prior graft needs to be removed. The chronic inflammation is so persistent that you really can't wait this processes out. Also the inflammation is doing harm to the eyelid. Depending on the clinical circumstance, the material may be removed and the eyelid allowed to heal before performing definitive lower eyelid reconstruction. In other cases, it is possible to remove the failing graft and replace it at the same surgery. This is a decision that has to be individualized. An in person assessment is needed to determine precisely your situation and what is best for the circumstances. Definitive reconstruction is possible. I am so sorry you are dealing this this challenge.