I'm struggling with a weak chin/neck fat/skin. What is the best way to get this result? (Photo)

You would benefit from more chin projection with 3 options: Fillers, Chin implant, or a sliding genioplasty.  None of these options can sculpt your neck as acutely as you photoshopped. During your consultation your physician can properly examine your entire face and better assess which option would get you closest to your goal.  Best wishes

So an implant is a good idea in your case as it will give you a stronger profile and exaggerate your neck shape. I have a lot of experience with chin volume using fillers and at least for you its a temporary way for you to see what an implant might look like. If you like the change then try an implant as a second procedure, otherwise, fillers, especially long lasting filler like sculptra might be your long term answer. Hope that helps,Adam Goodwin

 Hi, I have performed many facial shaping procedures, including Chin Augmentation with dermal fillers or silastic chin implants, for over 30 years.  from the photo, your chin is quite weak with a slight amount of fat under the chin.  When the chin is weak, this creates an imbalance making the nose appear larger, the mid face top heavy, the lower face looks short, de-emphasizes the lips and allows early formation of a "double chin".  
 Proper placement of a silastic chin implant adds forward projection to the chin thereby creating harmony and balance to the lower face.  Using the same incision, liposuction can be performed to reduce the fat and further shape the neck.  Excess skin, from below the chin, can also be removed through the same incision.  
 I have found that placement of a silastic chin implant, through a small curved incision under the chin (also allows excess skin removal) to be very safe, quick, highly effective and far less invasive than a sliding genioplasty (requires extensive tissue dissection, bone cuts and placement of metal screws and plates to secure the cut bone segments).  I perform chin implant surgery in 30 minutes or less, often using a local anesthetic alone.  In my opinion, you are a good candidate for chin implant surgery.  
Hope this helps

The image is a reasonable simulation of a lower jaw advancement surgery with a sliding genioplasty. Talk to an orthodontist or Maxillofacial surgeon for information and assessment.