What should I do about complications from a Mid face/Neck lift, 4 1/2 weeks post-op? (photos)

You have significant swelling of the upper neck still.  It appears as though there may be some scar tissue at the neck crease impeding the drainage of the edema.  You also have some irregular areas underneath this.  I would recommend some massage over the swelling to start to get the edema draining and to start softening the area.  This is going to be a slow process.  Warm compresses may help.  It is hard to tell if all of this is going to smooth out for you.  Some ibuprofen may also help as an anti-inflammatory.   

In general it is best to remove a hematoma as a complication of a facelift as soon as it is recognized. This will decrease the bruising and swelling. Most of the time the final result will be unaffected but significant scarring might require a revision. At the moment it's too early to tell.

Without looking at and touching your neck it is not possible for me to give you an exact answer. If you did have a hematoma following a facelift it is very common to see some fibrosis and contraction in the area where the hematoma occurred. This is why we like to drain them as much as possible to reduce the fibrosis that develops. When the involved area is small it will usually get better with massage and stretching exercises. In large cases re-operation is occasionally needed. Talk to your surgeon. If you are not getting answers get a second opinion.
Hope this helps.