Skin discoloration refers to any change in your natural skin tone. Common causes include birthmarks, infection, and skin pigmentation disorders. Some birthmarks, such as dermal melanocytosis ...

Discoloration around the lips and tongue may appear gray or white in people with darker skin, and the bluish tinge may be ...

could lead to over-lightening your natural skin color (called “ghosting”), and in rare cases, it can even cause a condition called exogenous ochronosis, or dark, bluish-gray discoloration.