Hi, I can understand your concern for the dark complexion in your daughter. You have not mentioned the exact age of your daughter. If she is below 16 years then should not do nay type of treatment and try to maintain by diet basically. The most important part in treatment is by lightening agents such as Kojic acid or azelaic acid cream application which you can use under dermatological guidance. The most important thing is sun protection by all measures. Eat healthy diet containing lot of Vitamin A and Vitamin C. Do not try applying over the counter products as these can further aggravate the situation. Protect herself from direct sunlight. Use a good sunscreen on exposed area for 2-3 times and let her drink plenty of liquids everyday. You should meet a dermatologist to plan the best treatment according to grade of pigmentation. All the best.