One Eye Looks Different After Upper Blepharoplasty

One week after any cosmetic surgery is too soon to make any decisions about final outcomes. You will need to wait at least 2 months, not weeks, to see how you are healing. The differences you are noticing now are most likely due to swelling...even if you sleep with your head turned to the side, you can develop more swelling on the side that is down.
Sometimes after surgery, people notice asymmetries that they never noticed before. You might want to look at some old photos of yourself and see if both eyes were symmetric before your surgery.
On the outside chance that your surgical results are asymmetric, it is very easy to remove a little more skin to even things up. So be patient, give it more time to heal, and don't worry.

Thanks for the question -
It is too early to tell smaller differences in symmetry. Things that can be of concern at this point would include inability to close your eyes and protect your cornea, wound healing problems, infection or major asymmetry.
As always, it is vital that you stay in touch with your surgeon as your post-op course progresses. Self photography to document your progress can be helpful as well.
I hope this helps.

Since it has only been a week from your surgery, swelling still has not subsided. It can take upwards of two months for the swelling to subside. Also look at your preoperative pictures to make sure that there was not preexisting asymmetry with regards to the eyelids.