Melanocytic nevus https://en.wikipedia.org/wiki/Nevus
Melanocytic nevus is a type of melanocytic tumor that contains nevus cells. The majority of nevi appear during the first two decades of life, with about one in every 100 babies being born with nevi. Acquired nevi are a form of benign neoplasm, while congenital nevi are considered a minor malformation or hamartoma and may carry a higher risk for melanoma. Benign nevi are circular or oval and are usually small (commonly 1–3 mm), though some can be larger than a typical pencil eraser (≈5 mm). Some nevi have hair.

Treatment
Laser surgery is commonly used to cosmetically remove small nevi. If the lesion is larger than 4–5 mm, surgical excision may be required. In young children, a nevus larger than 2 mm is often difficult to remove completely without scarring.
#CO2 laser
#Er-YAG laser
More information ― English
References Effective Treatment of Congenital Melanocytic Nevus and Nevus Sebaceous Using the Pinhole Method with the Erbium-Doped Yttrium Aluminium Garnet Laser 25324667 
NIH
Congenital melanocytic nevus (CMN) is a melanocytic nevus that is either present at birth or appears during the latter stages of infancy. Nevus sebaceous has been described as the hamartomatous locus of an embryologically defective pilosebaceous unit. Here, we describe how we used the pinhole technique with an erbium-doped yttrium aluminium garnet (erbium : YAG) laser to treat nevi lesions in different patients.
 Malignant Melanoma 29262210 
NIH
A melanoma is a tumor produced by the malignant transformation of melanocytes. Melanocytes are derived from the neural crest; consequently, melanomas, although they usually occur on the skin, can arise in other locations where neural crest cells migrate, such as the gastrointestinal tract and brain. The five-year relative survival rate for patients with stage 0 melanoma is 97%, compared with about 10% for those with stage IV disease.