Yes, the skin of a sweet potato is edible. Eating the skin will add more nutrition to your plate such as fiber and potassium. Also baking them is a better choice than boiling. Boiling can cause water soluble nutrients to be lost.
Sweet potatoes are a great source of vitamin A. Vitamin A is important for keeping your eyes and skin healthy. Since vitamin A is a fat soluble vitamin, adding some healthy fat such as olive oil to your sweet potato can help you absorb more vitamin A.
My favorite way to eat sweet potatoes are baked and topped with a drizzle of olive oil, chopped walnuts, and a sprinkle of cinnamon.