A value of NULL indicates that the value is unknown. A value of NULL is different from an empty or zero value. No two null values are equal. Comparisons between two null values, or between a NULL and any other value, return unknown because the value of each NULL is unknown.
Skin Spots on the Face. Most causes of spots on face are harmless. They can be a variety of colors including white, red, black or brown. Common causes include cumulative sun exposure, acne, and skin tags. Keratoacanthoma (hyperkeratosis) is a lesion that grows rapidly, usually on areas exposed to the sun.
There are many types of dark spots: 1  Skin Spots (also known as uneven skin tone, dark spots, age spots, brown Spots, or liver spots) These are flat marks usually found on sun-exposed areas of skin like the backs of the hands and face. 2  Melasma. Melasma causes patches of dark pigmentation over the cheeks, chin or forehead.