You should use a sunscreen that is SPF 30 or higher for your face. It can be the same sunscreen used for your body and should cover every area of exposed skin. Ideally, the sunscreen should offer both UVA and UVB protection, which is often marked as "broad spectrum" or "full spectrum." It's possible for skin cancer to affect your lips, so it may also be helpful to use a lip balm that offers sun protection of SPF 30 or higher.