Am I a candidate for Kybella? (Photos)

I think you stated your diagnosis correctly yourself when you said you had a weak chin. You didn't say you had a fat neck. You said you have a weak chin. That is the correct answer, if the problem is one of facial or skeletal imbalance then ideally you should not be looking at fat removal as the treatment.  At 136 pounds I can't imagine you have much fat in that area. Kybella is unpredictable and can cause massive fat loss way beyond what you ever wish you signed up for.  Since the problem is skeletal and not fat, on top of that you don't have much fat in my opinion you're wasting your money and it will undergo an immense inflammation looking like a bullfrog for a week or two with virtually no benefit.  Your chin is slightly pointed which means chin implants can be used but with caution making sure you don't get an excess of pointed Chin. It's a little hard to explain but your mandible is small in relationship to your maxilla.  At the same time your man the bowl is pointed giving you a forward projected Chin despite the mandible being small.  This is probably the most challenging thing to correct in my opinion.  If this really bothers you you can try using fillers though I'm guessing at your age and what most 18-year-olds are up to having temporary treatments for facial aesthetics may not be your thing.  My opinion to you is do nothing. You're a good looking young guy. Enjoy life and don't look in the mirror so much.  Best, Mats Hagstrom MD