35 days after medial thigh lift, my left foot/ankle is swelling MUCH more than my right. Lymphatic system disturbed? (photos)

Thanks for your question and photos.
Swelling following any type of surgery is common but after things like a thigh or arm lift can be significant.  You certainly fall into this category.  The thing we worry about the most when seeing such unequal swelling is a blood clot in the deep veins (DVT).  You absolutely did the correct thing in making sure this was not the cause as it can be fatal if not treated.  
The surgery itself does compromise the natural lymphatic drainage of the leg leading to swelling.  Additionally, your internal anatomy, specifically the venous drainage, also has a role in this as well.
The good news is that it usually improves with time.  I agree with elevation of the leg as much as possible when sitting but make sure you keep walking on a regular basis.  I usually use compression stockings following thigh lifts as well.  Just make sure you get ones that go from the foot to high on the thigh.  Wear them as much as possible.  Lymphatic massage of the leg can also help reduce swelling and increase comfort.  Make sure you follow up with your surgeon.
Best wishes.