A mini neck lift with removal of fat above and below the platysma muscle and the platysma plasty can give a nice improvement to the jawline. A chin implant will give added projection to the chin to accentuate the jawline further. Chin implants are manufactured in a Variety of sizes and shapes which is always determined at the time of the consultation and examination.
For many examples of this combination, please see the link below to our neck lift/ chin implant photo Gallery
Chin mplant for receded chin. You may not need liposuction once chin implant is placed. You do NOT want a "skeletonized " neck which can happen if fat rival is done in patients with thin skin.
Looking at your photos, the best result would be achieved with both a chin implant and liposuction combined. The chin implant giving you a deeper neck and liposuction to improve your current neck. You are also young enough to benefit from the skin retraction needed to get the benefit of liposuction. By combining the procedures you would get an excellent result with one downtime. Also, your results should be subtle enough that everyone doesn't notice. As to the keloids, very few people keloid on the face. But, explain that to your surgeon and they should be able to treat early if you notice a change in your scar.