What effects does the complete lack of sunlight have on our skin?

I'm asking this because I never expose the skin of my buttocks and genitals to sun light, because.. well they are always under my pants or bath suit.What effects does the complete lack of sunlight have on our skin?
You lose melanin, which is the pigment in your skin.


Then it is nearly impossible for the area to become darker, or tan.


For example, for about three years, I did not expose my toes to sunlight.


I wore ballet flats every single day.


Now, the area of the skin is white (though the rest of my body is pretty dark), and it is impossible to tan.


I can lay out in the sun for hours and this area will not be affected.


I know a ton of people who have had this same problem.What effects does the complete lack of sunlight have on our skin?
Skin, well nothing really. Some of our body parts never see daylight.