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.
Dimples are especially common in the face, because the muscles pull the skin on the face around, instead of just pulling around bones. The face also has bits of body fat, which cause the dimples to be more visible. Most cheek dimples are the result of a shortened muscle, zygomaticus major, pulling on the skin. There are dimples in the chin and the elbows, as well. At rest, it's not noticeable, but as the muscles around it pull into a smile, its shortness creates divots in the face.