I am 3 and a half weeks post transconjunctival lower blepharoplasty. How do I decrease puffiness at this stage?

Than you for your question. You are in the early stages of the recovery process where swelling and bruising are common after surgery, which cause the puffiness. I suggest that you remain patient and simply follow the post op care instructions provided by your board certified facial plastic surgeon.
Best wishes,

At this point of your healing some swelling is quite normal.  See your surgeon for evaluation, as some alterations in your sleeping position, warm/cold compresses or alteration in diet might be helpful.

A photograph would be invaluable to help us answer your question.  Please consider reposting with a photograph so that we can be more specific.

You are still early in your recovery. Expect a gradual improvement
for the next few months. Keep your doctor's appointments and 
notified him if any concerns. Best wishes.

Puffiness can take a while as the swelling will likely improve over the first 6-8 weeks. If concerned, discuss with your surgeon.

Thank you for your question.  You are still only 3.5 weeks post op which is still early in the recovery period.  Continue to sleep elevated , and follow up with your Plastic Surgeon.  It takes a couple months to see the final results. 

Swelling is normal for the first 4-6 weeks, and depending on the person, sometimes even for a little bit longer than that. The first recovery milestone usually occurs at the 6 week mark, when the majority of the swelling subsides.
Generally, we suggest a few things that can help swelling, such as cold compresses and massaging the cheek bone by placing your finger on the cheek bone near the nose and sliding it over to your ear. This massage helps to drain excess fluid that has collected under your eyes.
If you are concerned and wish to have someone take a look, I would suggest seeing your surgeon or an oculoplastic surgeon, which is an ophthalmologist with a concentration in plastic surgery specifically around the eyelids.

Another 3 weeks should make a big difference in your puffiness. To accelerate your healing - keep your head elevated above your chest at night, sleep on your back, avoid added salt in your diet, keep your blood pressure under control if that is an issue. Certain medical conditions and medications may prolong swelling - so be sure to have your medical check-ups particularly if you have heart, lung, kidney, thyroid or blood pressure problems and/or if you are overweight. Best wishes.