Botox (as well as the other two FDA-approved neuromodulators Dysport & Xeomin) may be used to improve some degrees of neck sagging, vertical (playsmal) bands, and "necklace" lines.
The Nefertiti Lift (named after the stepmother of King Tut whose famous statue possesses the paradigmatic perfectly straight and tight jawline) has been used successfully to lift the lowest portion of the face and secondarily the uppermost portion of the neck. With this technique, microdroplets of Botox (or the others) are injected along the jawline as well as into the vertical neckbands that become accentuated upon gritting the teeth.
Injected in this fashion, Botox slighten weakens the downward pull of the muscles thereby giving a competitive advantage to the muscles above the jaw, which then pull the lower jawline and upper neck slightly upward straightening them. Mild degrees of jowling and neck laxity can be treated easily in this fashion and the results, as with all Botox injections, may be seen within one week following treatment.
Treating platysmal banding with Botox is certainly nothing new. I have personally been doing this since the mid-1990s. Platysmal bands are those long vertical ropey bands on the front of the neck. Microdroplets of Botox injected up and down the bands can weaken the muscle tension sufficiently to allow the overlying skin to redrape itself more smoothly.
Botox treatment of the so-called "necklace" lines, those parallel arrays of horizontal wrinkles that encircle the neck, is also not new having been introduced about the same time as the treatment for platysmal bands.
The major downside of Botox neck rejuvenation is that not everyone responds, not everyone responds to the same degree, and the results generally last about six months for those that do.
The concomitant use of volumizing fillers, however, such as Radiesse to straighten the jawline can further enhance the effects of Botox and prolong the results significantly. Likewise, the use of microdroplets of Juvederm Ultra XC along with Botox is an excellent treatment for the necklace lines. And, more recently, I have found that the addition of Juvederm UltraPlus XC injected along a horizontal line extending across the border between the neckline and chin line, as well as within certain areas directly under the chin, can supplement the "Nefertiti Lift" by stretching some of the laxity and by providing the visual illusion of a more well defined cervico-mental (neck-chin) angle.