My (m, 35) chin is recessed about 12mm posterior to my upper lip. It chin also lacks height. (My LAFH is ~75mm: upper lip ~25mm, lower lip ~25mm, chin ~25mm.) I have a thick...
I'm also not a doctor, and unlike Jo I haven't had any surgery on my neck, but I do have it scheduled. Also, I'm a man, but we're the same age.
Often people with "heavy" necks have a combination of problems, including a chin...