Why is there a puffy ridge under my eye after Blepharoplasty? It wasn't there pre-op. Can it be fixed? (photos)

What you are seeing is the orbicularis muscle that is under the lash area.   After surgery this muscle may stay swollen for awhile so it may resolve.  Taking out the fat under the eye may accentuate this muscle. You will need to give it more time to heal.  You may need some revision after 6 months - to either thin out this muscle, or put some filler in under the muscle to hide the step off.  

Surgeons often make the mistake of thinking that all puffiness in the lower eyelid is caused by herniated orbital fat.  The fat of the matter fullness in the lower eyelid can be caused by a number of thing, not just herniated orbital fat.  If you put your finger on this new ridge and it is hard, you are feeling the orbital rim.  It is possible that the rim is more visible due to loss of muscle and fat that was providing a layer of volume to high the orbital rim.