This is a cobra neck deformity. This is related to excessive removal of the deep fat in between the platysma muscle bellies in the midline of the neck. It does not appear that the submandibular glands were reduced. It also appears that the platysma muscle has separated and there is now a gap out of the midline. I would recommend a deep plane neck lift to reduce the deeper fat further, sculpt the submandibular glands, repair the platysmal muscle bellies back together and very carefully perform superficial fat liposuction. You need to find an American Board of Plastic Surgery certified surgeon; ideally, this surgeon has also completed an aesthetic fellowship accredited by the Aesthetic Society.