Could I benefit from a mini V-line? (photos)

I would recommend a consultation to address the concerns you have along your chin and jawline. On the side or profile view, it does appear that you may have a weak chin that can be improved by removing some fat near the jaw angle. I would also consider fillers to give you a better idea of what you might look like and consider longer term a chin implant that comes in various sizes and shapes and can augment or define the areas of concern that you have.

It is impossible to see exactly what is a problem with your chin, jawline, neck from these photos, unfortunately. It seems, from your description, that chin implant with so many varieties of size and shape may be a better option than sliding genioplasty? Neck and jawline liposuction could be performed in the same time and would give you more predictable result than fat dissolving injections. In person consultation with a board certified plastic surgeon with good reputation in facial implants and face/neck surgery is recommended. Good luck.

While your chin can be reshaped with a t-shaped bony genioplasty, getting your jawline reduced or more defined is not so simple. Liposuction or fat dissolving injections are not going to more fully reveal the shape of your jawline bone. You have thicker soft tissue which is not fat. To fully show your jawline bone you need a 3D CT scan of your lower jaw which is the preoperative method to determine teh shape of your jawbone as well as what would be the best procedure to narrow it.