Use sunscreen on any exposed areas. An SPF (Sun Protection Factor – солнцезащитный фактор) of 45+ is recommended for it allows even the fairest skinned folks to stay out in the sun for a few hours before reapplying. Try Vaseline or chapstick on your lips. Follow the instructions on sunscreen carefully; reapply when it says to reapply or it may not work properly. Always reapply after leaving the water, as it'll have washed off.
Don't forget hard-to-reach places. Don't forget to cover the backs of your knees, back of your neck, elbows and back of your ears (if you have short hair). Feet should also be included if you are wearing sandals, flip-flops (вьетнамки) or going barefoot. Even these places can hurt a lot with sunburn.