These stains can often psychologically be disturbing. They can, but not always, be camouflaged or covered by permanent make up or medical tattoo.
Vitiligo in the face, a skin disorder, has no pigment cells in the skin produce pigment (melanin) anymore. This appears in (small) white spots on the skin surface. It will probably be a minor derailment of the immune system so the body creates antibodies against its own pigment cells.
The result is non-aesthetic discolored spots on the skin of vitiligo.