One Side of my Face Lower Than the Other?

100% of people have facial asymmetry and it's important to remember that while this can be corrected and improved, I tell all my patients that there is asymmetry to the bone, muscles etc. The same way you are right-handed or left-handed, when you smile the muscle attachments and skin attachments are different explaining why some people have smirks, dimples etc. The asymmetry is more prominent in some people than others.  There are things we can do to make things better, but at the end of the day, I tell my patients there's a 100% chance they will still be asymmetric after any surgery anywhere in the body. We usually try to make people more symmetric especially if it is something that bothers them. Sometimes people only want a facelift on one side or certain procedures without targeting both sides of the body, and this is something that is available and possible.
If you are concerned by your facial asymmetry, I would recommend that you see a board-certified plastic surgeon in your area that is a member of both ASPS & ASAPS and performs a lot of facelifts but also offers all the nonsurgical options such as Botox injectables and laser treatments. Sometimes injections and nonsurgical treatments can improve asymmetry without any surgery.  
I hope my answer helps you. If my answer helps, please take a moment to up vote this answer on the “respond” button on the top right.  Have a great day.

Without a picture, it is hard to make an assessment and give any advice on what procedures can be done. Always remember two things: 1) No one stares at you like you stare at you and 2) the sides of the face are sisters, not twins, and will never be perfectly symmetrical. Going off of the first saying, as much as the asymmetry might bother you, it is most likely something that other people who met you in passing will not even notice. At only 26 years old, you are very young to be considering a facelift. If the asymmetry is seriously something you think you can not live with, then I recommend consulting with a board-certified plastic surgeon in person to discuss your concerns and see if there are any nonsurgical procedures such as fillers or Botox that can help with your asymmetry. Sometimes, correcting one asymmetry, such as the lips, or the teeth, can make everything else look balanced. But remember, “less is more,” and there is nothing more frustrating than to see young people “over surgerized” which can obliterate their natural beauty!

First off, let me say that every single person on the planet is asymmetric. no two sides of the mouth are the same, no two eyes are the same, no two cheeks are the same, etc. Mild asymmetry is completely normal, and some people have more significant asymmetry. If mild and bothersome, they can sometimes be camouflaged with filler on the more deficient side, fat grafting, or even facial implants. If your teeth or bite is misaligned that may require surgical correction with an oral surgeon. I recommend meeting with a surgeon for an honest and open discussion about your concerns, they may be completely normal asymmetries!
-David Mattos, New York Plastic Surgical Group