Yes, they do...although an area of skin that has been damaged
may heal with either hyper- or hypopigmentation. The melanocytes
are at the base of the epidermis and transfer melanin pigment to
adjacent keratinocytes. Damage to the superficial layer of the skin
(epidermis) will heal without scarring. Damage to deeper levels
will cause scarring. Adjacent melanocytes can migrate in during
healing but depending on the case, the scar may be darker or
lighter than usual.
As for vitiligo, the cause and pathogenesis is not well understood.
Some believe it is an autoimmune disease but other factors such as
genetics and lack of melanocyte growth factors may contribute to
it.