Crepey, Saggy Neck at 39, What Are My Options?

Thank you for sharing your question and your photograph. Here are my thoughts. 
You are young, but not too young to have this problem. While there are a number of contributing factors to aging of the neck, some people are just burdened with poor genetics and inelastic tissues. 
Sometimes a weak chin or jawline will accelerate an aged appearance of the neck, but I can't evaluate your bone structure from the single photograph provided. Not only is your skin inelastic, but there are some band-like deposits of subcutaneous fat in your neck and there is early sagging of the deeper structures (e.g. platysma muscle), especially on the left side. 
I think the best and longest lasting result would be achieved with a lower face and neck lift  including platysmaplasty.  Neck lift alone is a reasonable second choice, but would not be as effective in creating a smooth jawline.
My patients have seen good improvement of crepey and inelastic skin when treated with a combination of  microneedle radiofrequency (Profound RF) and Fractional CO2 laser; however, energy based devices will not tighten or support the deeper structures and will be less effective overall than a surgical procedure.  My very best.

"These are all natural parts of the aging process. What we can do is try preventative treatments or get a neck lift / face lift earlier in the aging process. There are numerous non-surgical options available, and some can be used in combination to get best outcomes, but you would need a consultation with an expert.

Some options for skin tightening include:

- Thermage radiofrequency to heat the skin, tighten it over time, and prevent the aging process
- Ultherapy high-intensity ultrasound to contract the muscle, tighten the face and neck, and prevent the aging process
- PDO NovaThreads or InstaLift threads for immediate lifting without surgery and long-term collagen production
- Sculptra injections for collagen production to areas of the face and neck with crepey skin or early sagging
- BTL Exilis Ultra, Venus Legacy, and Thermi250 for monthly collagen stimulation with facials
- ThermiRF, Renuvion (J Plasma), or Inmode BodyTite for internal heating and tightening with or without surgery
- Fillers (or facial implants) to contour the jawline and chin to improve the appearance of the neck
- Face lift / neck lift with fat grafting and fillers if you need a significant improvement​

​I would suggest getting a formal evaluation with a cosmetic dermatologist. Best, Dr. Emer​​​​"

The impact of pregnancy weight is significant for many women, and affects various parts of the face and body. The pattern of skin excess under the chin is usually treated better by a combination of facelift and necklift because the more vertical vector of the facelift controls the skin tightening in that area.You can evaluate which approach would have better impact for you by tensioning the skin either in front of the sideburns (facelift simulation) or earlobes ( necklift simulation). If you feel the improvement from a necklift simulation is adequate, it typically translates into a similar effect in surgery. It is important to do the simulation with mild tension. With high tension, which cannot be replicated by surgery, the vector no longer matters. If the necklift simulation appears short of expectations, a facelift and necklift are more likely to address your concerns.

Thank you for your question and photos. Based on your photos provided, you do have excess skin and this can be caused by weight gain/and or loss as well as genetics and sun damage. You are an ideal candidate for a neck lift. I would advise you to schedule a consultation with a board certified plastic surgeon for a detailed examination to discuss all possible treatment options and what your expectations are.

A surgical neck lift has the ability to rearrange and adjust amounts of tissue, thus they can remove excess skin and tighten muscle bands. Nonsurgical skin tightening treatments can improve the quality of the tissue left behind,  which can have an immediate affect and help age proof your neck and jawline moving forward. 
Overall, tightening can have improvement to the jowls and neck to some degree, but they do not truly alter the amount of position of those tissues.  When true tissue excess is present, whether that is skin, fat or muscle, surgery is needed. To ensure you are receiving the highest level of care, seek out a modernly trained, new-school dermatologic surgeon, oculoplastic surgeon, facial plastic surgeon or plastic surgeon who is board certified and fellowship trained in one of these “core four” cosmetic specialties. Membership in organizations like the American Academy of Facial Plastic and Reconstructive Surgery help to identify a highly trained surgeon.Cameron Chesnut #realself hall of fame Physician 

There are many options for improving the texture and skin laxity of the neck skin, with a number of skin-tightening lasers such as Thermage, SkinTyte and Ultraformer III that improve skin laxity with minimal or no down-time. These however need to be continued for ongoing improvement.The surface texture of the skin can be improved by laser resurfacing with the HALO and Medical grade Fraxel DUAL lasers the best for this, although there are other options such as needling.
For a more long-lasting result then a lower facelift and necklift is the best option to improve skin laxity, although these do not improve the actual skin texture, so other resurfacing treatments may be necessary.