Can a high smas facelift, lift corners of upper lip/corner of mouth? Can it improve or reverse a bad midface lift?

Lifting the SMAS can improve the look of your lower face, including drooping mouth corners. Performed expertly, it can be used to revise an unsatisfactory mid-face lift. Be sure to work with a facial plastic surgeon who takes the time to evaluate your anatomy properly and find a solution that looks harmonious and natural. I hope this helps.

I'm sorry about your disappointing results.  To really help answer your question, an in person exam or at least several pictures would be needed.  But, SMAS manipulation can alter different aspects of the facial contour depending on the vector of pull applied.  There are many different techniques that could be employed to correct sub-optimal facelfit results.

Thank you for sharing your question.  Though nothing replaces an in-person examination it is possible to subtly lift the corners of the mouth with a high SMAS lift. I would see a series of ASPS board certified plastic surgeons in consultation to have an assessment of your tissues made to obtain the best information.