In general there is typically a different amount of swelling (mild amount) and/or bruising on each side of the face after a facial rejuvenation procedure like fat transfer or even a facelift, especially after three days. With time the symmetry will or should appear. If there is ever a significant difference with pain then you should contact your surgeon to make sure everything is healing normally.
Tip: making sure you sleep on your back and not on your side may be helpful as sleeping on your side can create more swelling on the the dependent (lower) side.
I hope this helps.
It is not uncommon to have some mild, uneven swelling after fat transfer surgery. The trauma from surgery will always cause bruising and swelling after a procedure, that may be worse on one side compared to the other. Allow up to three months for the fat to "settle", and at that time you will have a better idea of your result. Good Luck