Fluid Retention Due to Blepharoplasty?

Your results are satisfactory and the effects of surgery can take as long as a year to settle. I have seen mild edema (swelling) in lids past six months, so be patient.

In comparison to your before picture, your after picture looks very nice. You have a smooth lower lid and lid/cheek junction. Unless there is something that is not apparent in the picture, you should be very happy with the result.

Let's start with your preop photo. In the region of your lower eyelid/upper cheek, you have a "roll" below the lash line on both lower eyelids. Then there is a second "bulge" below the "roll", that many people would call a "lower eyelid bag." The upper "roll" is a very common finding in the asian eyelid, and corresponds to the orbicularis muscle and its attachments to the muscles around the eye. The lower "bulge" is orbital fat that is visible through your thin eyelid skin and is accentuated by the hollows above and below it.
As we age, we lose volume in our face, and our skin thins. This allows the underlying hollows to become unveiled. Surgery to remove fat alone does not correctly address these hollows. In contrast, volume enhancing procedures to fill the hollows hides bulges and rolls to provide a natural appearing result.
Your surgery to remove fat can only affect the lower "bulge", and that's exactly what we see in your post-op photo. Where there was once a bulge, there is now a hollow area. The "roll" of orbicularis muscle is still there, but less defined since it descends into the hollow area of fat removal just below. This leaves your eyelid looking a little hollow, and accentuates your tear trough deformity. The tear trough is the hollow area below your eyelid that starts near the nose at the inner corner of the eye, and curves down toward the cheek. If you touch this area with your finger, you can feel the orbital rim bone where there is the hollowing.
In my opinion, you look a little too hollow now in the lower eyelid and tear trough area. This accentuates the fullness of the orbicularis roll by the lashes, and may make you feel "puffy", because the lower eyelid contour does not smoothly integrate into the cheek. After you have had sufficient time to heal, I think you would be a good candidate for a volume enhancing procedure to fill the hollow areas. Options include fillers such as Restylane, or a fat transfer procedure. This would softly improve the contour of your lower eyelids and upper cheek.

From your pictures and description, it sounds like you had a subconjunctival lower blepharoplasty. The amount of swelling in your lower lids appears to be normal for the 8th week after surgery. The swelling should continue to decrease over the next several months. I will occasionally give methylprednisolone over 6 days if the swelling is significant.

Fluid retention after blepharoplasty can be problematic in some patients. Altitude, air pressure changes, hormones, and allergies can all affect fluid retention. A low-salt diet would be recommended at this point. At three to four months after the surgery if there is still fluid retention, one has to consider whether or not there is residual fat that was missed at the original surgery.