What would be the optimal kind of procedure to get a sharper, less "droopy" neck skin under my jawline? (photos)

For a more defined jawline to strengthen your profile (and help prevent the dreaded jawline "jowl" sagging), we use injectable fillers like Revanesse Versa - a filler known to limit swelling and give subtle, soft enhancements - or Radiesse. Using a cannula to limit pain and swelling, we inject on the bone in strategic points to get more lift and shaping, resulting in a more contoured lower face and defined, structured jawline. I would suggest getting a formal evaluation with a facial sculpting expert. Best, Dr. Emer

I don't really see much of an issue with droopy neck skin in your photos. It is possible that there could be a small amount of fullness from fat under your chin, but an examination of you would be needed to determine that. If there is some fat, Kybella could be used for that area. I do not see any need to tighten the skin of your neck under your jawline. In regards to your hair, you could consider beginning finasteride or dutasteride orally.