Eyebrow Frozen After Lower Facelift, How is that Possible?

  Yes.  This can happen, just as other doctors have discussed with you.  But I am writing just to re-emphasize that in all likelihood this will get better with time.  It is VERY early after your procedure and the odds are STRONGLY in your favor that the brow elevation will return to normal over the next 6 months or so.

Temporary weakness of the face following facelift surgery is possible.  Don't panic at this early point.  The nerves can be stretched or stunned during surgery -- making the weakness temporary rather than permanent.  Give it time.  I would not surgically intervene for a minimum of 6-12 months.  Most people experience a return of function within that timeframe.

As others have noted, you probably have an injury to the frontal branch of the facial nerve.  This branch crosses the zygomatic arch in  a relatively superficial plane.  This is very likely to recover within the next few weeks to months.  Your Surgeon is likely to suggest Botox/Dysport to the normal side until recovery is complete.

You need to see your plastic surgeon ASAP. Your doctor needs to examine you and determine the exact cause of why you are unable to move your eyebrow. If you are in the LA I would be more than happy to examine you, as I have extensive experience in facial nerves.

During a facelift, big or small, the branches of the facial nerve lie just deep to where skin gets lifted and the suspensory tissues get tightened. The facial nerve branches emanate just in front of the earlobe, sending branches as high as the brow and as low as the jawline. These branches allow facial movement throughout the face. The nerve branch to the brow may get bruised or weakened with surgery and take some time to get strong again - this is the most common scenario with postoperative brow weakness after facelift. It sounds like this is what you are going through and it's not unusual to have one side weak and one side ok. This should completely improve over the course of the next 3-6 months. You will need to follow along with your plastic surgeon to assure improvement. If it does not, the nerve may need to be explored

Injury to the frontal branch of the facial nerve is an attendant risk to facelift surgery.  You really do need to discuss with your surgeon whether the nerve may have been at risk from the dissection itself, or possibly from a suture placed at the time of the surgery.  From what you describe, the latter may be more likely.   There is a (sentinel) vein that runs alongside the temporal branch of the facial nerve, and the swelling is suggestive that both the vein and nerve may have been traumatized at the time of the surgery.  It does sound like the surgery was primarily directed at the lower face rather than your brow.  It may be that the nerve is involved in a suture, and if so it may be necessary to re-explore this. 

Don't worry most of these recover. Your nerves regenerate at a best rate of 1mm per day. Your physician should guide you in this recovery. The face lift dissection, sutures binding and even the electrocautery are just some of the causes for the nerve injury. It will recover though.
 

One risk in facelifting is damage to the facial nerve which is the nerve that moves the face- including the eyebrow. In a minifacelift, the facial nerve is below the plane of dissection. Theoretically, the nerve could be trapped in a stitch and there can be resulting weakness. And there are instances when excess swelling can lead to weakness of the nerve too. Your surgeon needs to evaluate you to establish a plan of action. 

A lower facelift can cause the problem you describe only if the disection injured the facial nerve. I do not know how high the surgeon went with his disection or how deep with regards to the area in front of the ear. There is nothing to do at this point but keep your fingers crossed. Hopefully the problem will resolve or improve in the near future. If not you need to see what your surgeon suggests as a way to deal with the problem.

I have performed Face Lifts for over 20 years and from what you're describing the temporal branch of the left facial nerve may have been injured during the Face Lift.  This branch travels through the temple region and should remain deep to the Face Lift dissection but injuries have been reported in the literature.  You might want to follow up and ask this question to the plastic and cosmetic surgeon that did your Face Lift (min face Lift) surgery.