Can an upper blepharoplasty crease made too high (8mm) be lowered? What are the revision possibilities?

The biggest issue based on the photos you have provided is the left upper eyelid ptosis. I do recommend being patient and giving the eyelids more time to heal. While an 8 mm crease height might be okay in a Western eyelid, it is generally better to have a lower crease height in and Asian eyelid. My target height for the crease the Asian eyelid is 5.5 to 6.5 mm for initial surgery. There are reasons when a deviation from these numbers is warranted. The other issue is the control of the eyelid platform skin below the eyelid crease. That is done with a procedure called an anchor blepharoplasty. This technique results in a direct adhesion between the eyelid platform skin and muscle and the leavtor aponeurosis. Most eyelid surgeons are not comfortable exposing the levator aponeurosis.  For that reason the often performed and inaccurately described supra tarsal fixation. I do not believe that you had an anchor procedure with your surgery. You have bilateral upper eyelid eyelash ptosis. In the lateral pictures, the eyelid platform space is bulky. This is not the result of swelling. This is the result of not snugging the eyelid platform skin and muscle to the levator aponeurosis. These issues including the ptosis can be addressed with revisional surgery. Even the upper eyelid crease can be lowered. Generally it would be helpful for you to heal for another couple of months before having a consultation for upper eyelid surgical revision. It is best when to have this work after the eyelid has healed for 6 months. 

Best to allow longer healing and then re-evaluate. You may have underlying ptosis which changes the eyelid crease. See an oculoplastic surgeon.