This is skin necrosis.
That is a very bad thing. What has your surgeon told you? Has your surgeon even seen this? If you smoke-please stop right now and pick up the phone and call your surgeon. This is a very bad complication you are having and it is not common or normal. This occurs when the skin is dissected at the time of lower skin incision blepharoplasty. The most common cause is poor microcirculation associated with smoking and diabetes. It can be seen also if the dissection is too close to the subdermal vascular plexus under the skin. I do not recommend surgical debridement in these cases because it is very difficult to know which parts of the skin will actually survive. I do recommend immediately smoking cessation, daily hyperbaric oxygen treatment, the benefit of which is unproven for this, and copious ointment on the skin. As ugly as this looks, I have seen amazing recoveries and I have also had to reconstruct eyelids referred to me with this issue. Your surgeon should see you today and make a plan for careful support and management of this. Please consider reposting and letting us know how things went.
Lower blepharoplasty healing
The picture you've posted raises more questions than it answers. Clearly you and your surgeon know the details of your procedure which you have not shared with us. If you had a basic blepharoplasty for cosmetic reasons then clearly you are having skin necrosis and scabbing. I doubt that is what is going on. You need to be seen by your facial plastic or occuloplastic surgeon immediately.
Skin color darkened and blackish after lower eyelid surgery
The photo you provided does not depict normal healing after a usual cosmetic lower eyelid surgery. More information about your surgery would be helpful. What was the surgery done for and was it done on both eyes or only one? It would be important to know exactly what was done during the surgery as well. The black area below your eye could be scabbing or necrosis. It would be best to contact your surgeon since he or she will have all the information about your particular procedure and should be able to advise you.
Healing after blepharoplasty
It would be helpful to know what surgery was done on your lower lid. The photo appears to show a skin graft, was this a reconstructive procedure? This is not a normal appearance following a blepharoplasty and may show necrosis. You should follow up with your surgeon immediately.
Unusual discoloration of eyelid following surgery
Thank you for sharing your question. Without knowing what surgery was performed, it is hard to evaluate your healing process. It appears you had skin grafting. Please repost your question with description of surgery.Thanks.