A facelift / necklift is an excellent operation to lift the soft tissues of the face and neck, tighten the underlying muscle, and remove the excess saggy skin. Aging continues after surgery, however, so most patients will see some recurrence of skin laxity and tissue decent, as they get older - sooner or later. The amount of correction and longevity of the result are dependent on many factors including the extent of the surgery, patient age, previous surgery in the area, sun exposure, smoking, and genetics. In your case, you have the added burden of having a connective tissue disorder that will accelerate the process of aging. A revision lift is usually possible, however, you will have to weight the pros and cons given you previous experience and you new diagnosis. Consultation with a surgeon certified by the American Board of Plastic Surgery would be the next best step. See the link below for more info.