I would say yes see an ophthalmologist mainly for your peace of mind. That is a classic cause of sudden Horner's (neck surgery). There is no treatment and often it causes no problem.
JCH MD
Thank you for your answer. My daughter is very concerned about her droopy eye..it is noticiable and worse at night. When she works out half her face stays white and the other gets red. She won't even go to the gym. Also the jaw pain is excruitating. Wouldn't a neurologist be able to assist in any way or test to see if the nerve might repair itself? We were told to wait a year and if no imporvement the only thing she could do is to have plastic surgery on the eye for cosmetic reasons.
The small pupil and droopy like are common. The lid may get better. If not a lid lifting operation can help. The facial sweating problem is usual. The PAIN concerns me. A sudden onset painful Horner's syndrome can be due to a disecting carotid aneurysm which is potentially ultra serious. It's not likely but I would contact a neurologist as soon as possible.
JCH MD