Dark circle after lower eyelid fat removal. (photo)

SOrry to hear about your concerns. I assume you have posted a pre/post photo combination and thus I certainly see a few things here. For one, you seem to have some redundant skin on the pre-visit however it is unclear if you have extra-fat. Also, you can see you had some darkness under the eyes pre-operatively however it appeared more "shadowed." Once you had the surgery, the excess skin is still present to some extent and thus it has created these small wrinkles. The darkness is now more pronounced as you don't have it hidden by the shadows thus you get a bit of hallowing under your eyes. My personal opinion and advice would be to really consider how much you want to "chase" a solution. I'm a believer in, Rule #1 - Don't make it worse. Trying non-surgical things like fillers, creams, lasers are all excellent to start with and may really help with minimal chance of making things worse. If these don't work, more agressive/permanent changes can be tried like fat transplants, re-excisions, etc. But here in Ottawa, Canada at my clinic, i recommend caution to people who have results that are not perfect. I hope things work out for you. 

I am assuming that the first picture is post-op, and the one on the right pre-op.   If this is so, you have hollowing post-op due to the fat excision.  You have a little bit of proptosis too, so that it looks pretty dark now.  The fine lines occur because you don't have the fat supporting the skin.  You need to have volume put back into the lids.  The easiest way to do this is with a hyaluronic acid filler such as restylane or belotero.  Another option would be a fat transfer.          

You have relative proptosis with a weak lower eyelid orbital rim.  I think your surgeon was heroic to make the improvement they did without compromising the position of your lower.  Dark circles are inherent to the anatomy of the lower eyelid due to thin skin overlying the lower eyelid muscle, the orbicularis oculi.   Perhaps the safest approach here is to get hyaluronic acid filler to the orbital rim which will fill in the dark circle.  This does seem to help.  You need to find an injector who is very experience with this.

You were not a good candidate for a transconjunctival blepharoplasty as it has enhanced the hollowness around your lower eyelids.  You may benefit from a filler to this area such as fat and a topical agent such as teamine for the darkness.  

From your provided photos, you had darkening before your surgery as well.  I think the fat removal was done well because your lower eyelids are no longer as puffy and look smoother with the cheek.  Overall, I think your lower eyelids look better, but gentle elevation of your outer corners of your eyelids could be done.  Hyaluronic acid filler can sometimes improve the lower eyelids a bit more, but I would proceed with caution.  Getting the skin darkness to actually change is much harder and very few treatments are all that helpful.  I have not found bleaching agents or retina A to be that helpful.