My face has a two tone too it, why?

May need an exam...: Normal people have whatever skin colors nature gives them, which ranges from very light to very dark. Also, nobody is just one color (or one shade of light/dark) over her whole body. Avoiding sunlight keeps skin lighter and more even, but one will need to take extra vitamin d if avoiding sunlight. Very light areas can be due to eczema or vitiligo; very dark areas may be due to hormonal problems.

Different reasons: There are multiple reason to have discoloration of the skin. Sun exposure will darken the skin of anyone, regardless of skin color. Rashes or other skin problems can change the color of the skin as well. Without a picture it is hard to be more specific. See you primary doctor or dermatologist for further evaluation and appropriate workup.