Summarize the following:
Lemon juice is a natural bleaching agent and can be used on your skin when you mix it with an equal amount of water.  For the best results, leave the liquid on the dark spot for at least 10 minutes and then rinse it away. Potatoes are another natural bleaching agent that can be used on your skin without a lot of preparation needed.  Simply cut a raw potato into thin slices and apply a slice to your dark spots.  Allow the potato slice to sit on your skin for about 20-30 minutes before removing it. Mix 2-3 tablespoons of gram flour and ¼ teaspoon of turmeric powder in a bowl.  Add lemon or cucumber juice and approximately ½ teaspoon of milk to the powder mixture.  Mix these four ingredients together until it forms a smooth paste.  Apply the mask to the dark patches on your skin for 10 minutes.  The mask will dry as you wait. Use warm water to gently remove the mask after the 10 minutes is finished. Use the mask on your dark patches twice a week until the patches have lightened to where you're comfortable. The milk measurement is approximate.  You'll want to add enough to turn the mixture into a paste. If you have sensitive skin, use cucumber juice rather than lemon juice. Note that turmeric powder can easily stain fabrics, so be careful with your clothes and towels. Gram flour is flour made from ground-up chickpeas. While you're working on reducing or eliminating the dark patches on your skin, do not scratch them or rub at them with a pumice stone or brush.  This is also good advice in general, as rubbing your skin with rough items can cause damage.  Use natural items for exfoliation instead, such as loofahs and sponges. Use soap that has the same pH level as your skin (5.5). Always shower after you've been exercising or sweating for any reason.
Try a homemade lemon juice bleaching agent. Use potatoes to help bleach your skin. Make a turmeric mask. Avoid scratching your sunburn patches while they heal.