How can I remove this dark line on my neck? (Photos)

Most chemical peels remove the top layers of skin through exfoliation. Although this may initially thin the skin, the goal is to stimulate new skin with denser collagen to form. Deep chemical peels and lasers tend to give you more collagen-rich skin that is healthier and more youthful.
The amount of skin recovery really depends on the depth of your chemical peel. Light chemical peels have little to no downtime, whereas deeper chemical peels may penetrate the dermis and cause 7-10 days of skin recovery and peeling. During the initial dryness and peeling stage, your skin may become noticeably darker as the pigment is driven towards the surface of your skin. Redness, skin tightness, mild discomfort, and itching are all normal elements of recovery. We encourage patients to use a lightening SPF sunscreen during the day. It is advisable to avoid direct sunlight and picking of any dried or peeling skin.

Best,
Dr. Karamanoukian
Realself100 Surgeon