There is no substitute for surgery for the most significant and longest lasting improvements for the neck. Non invasive options that result in some noticeable but modest improvement include laser, peels, thermage, radiofrequency and ultherapy. Creams like Retin A slow the aging process but doesn't reverse it that much other than some textural improvement. See the below link for BioSpa to see more information on skin treatments.
For the best result consider a mini lift such as the MACS lift, Lite Lift and others will improve both the lower face(jawline) as well as the neck. A necklift mainly focuses on the neck. The best value and quickest recovery time in my experienced is from a mini-lift procedure.
An exam is always needed to determine how the specific causes of your undesired neck appearance. In particular there are 4 main factors that need to be evaluated:
1. the amount of redundant skin, excess fat below the chin, (requires neck or facelift)
2. banding of your neck mid-line neck muscles (platysmal bands) - requires platysmal plication (neck tightening)
3. elasticity of your skin. - requires laser or peels, thermage, ultherapy
4. a weak chin (supports the skin structure) - requires chin augmentation
Each of these components are dealt with in a different manner. For example, excess fat requires direct removal or liposuction (more common), widely spread playtsmal bands are brought together (neck tightening), and excess skin is removed with a lower facelift or neck lift (this can be done with minimal scars). Certain lasers and peels can help with elasticity problems and your photo seems to indicate adequate chin projection.
Traditional liposuction removes excess fat superficial to the platysmal muscle. A neck lift is able to remove fat both above and below the platysmal muscle and tighten it; this will give a more defined jaw/neck line. .The lax skin in your upper neck can be approached directly by a less invasive facelift in the mini-face lift such as the MAC or Lite Lift procedures. The least invasive would be one of these procedures which corrects the upper neck loose skin extremely well.. My own personal preference and in my hands the one with the least invasive approach is a Lite Lift which is performed in my office under local anesthesia with some oral sedation without the need for IV sedation or general anesthesia.
Always go to a board certified plastic surgeon with great experience in neck and face lifting.