"Blue Skin" is a rare but real genetic condition, medically known as Methemoglobinemia. In Methemoglobinemia, an abnormal amount of hemoglobin (responsible for distributing oxygen to the body) is produced. Since an abnormal amount of hemoglobin is produced, it's difficult for the hemoglobin to carry and release oxygen to body tissues, consequently turning skin and lips blue.
It would be very difficult to live with this disorder. We can only imagine the stares and strange looks one would receive with such a poignant color of skin.
As Christians, we aren't commanded to have "Blue Skin", but we are commanded to be different. Scripture is full of metaphors that describe our uniqueness: "Light of the World" (Matthew 5:14), "Salt of the Earth" (Matthew 5:13), "Shining Stars" (Philippians 2:15), "Ambassadors for Christ" (2 Corinthians 5:20), "Royal Priesthood" (1 Peter 2:9). Take your pick. Each one, in its own way, dares us to be different.
Regardless of your "shade", God sends the same message--"Be holy, as I am holy." (Leviticus 11:44)