Horner's Syndrome and Acne

My daughter was diagnosed with Horner's Syndrome seven years ago.  She is now 20 years old.  She has struggled with severe acne ever since she was diagnosed.  The acne is mostly on the right side of her face, where she has the droopy eye.  We have tried five different dermotologists over the years and tried just about every medication.  Nothing helps.  Not birth control, not Differin, not Retin-A, nothing.  I am wonder if her Horner's Syndrome is causing her acne?  And, if so, what can be done to get her some relief from the acne?