There are many reasons for melanin deposits on the neck, the common ones are nevus, acanthosis nigricans, post-inflammatory hyperpigmentation, etc. There are different treatments for different reasons, which usually include general treatment, medication, physical treatment and surgical treatment. 1. Pigmented nevus: If it is determined that melanin deposits are caused by pigmented nevus, physical methods such as laser or surgery are usually used to remove them. 2. Acanthosis nigricans: Acanthosis nigricans is one of the most common causes of hyperpigmentation on the neck, the specific etiology of which is unknown, and is currently considered to be a metabolic disorder-related disease, mostly occurring in obese patients. Treatment should first actively control diet and reduce weight, with weight control, most of the acanthosis nigricans will improve. At the same time, it can be treated with some medications, such as oral vitamin C, vitamin E, topical Vitamin E cream, Vitamin A cream and other treatments. 3. Post-inflammatory hyperpigmentation: hyperpigmentation will appear after inflammation of the skin, which can be reduced by itself, and can be accelerated by medication, such as oral vitamin C, topical hydroquinone cream, deoxy arbutin and so on. There are many reasons for melanosis, such as the symptoms, it is recommended to go to the hospital to clarify the cause of the disease, and then targeted treatment. Drugs need to be used in accordance with medical advice.