Can you tell me some way to limit or stop skin darkening when outside?

Block it: There are several ways to prevent darkening of the skin from the sun. First is to block the sun. Physically, you can do this by staying under an umbrella, wearing a hat or using a sun block such as those with zinc oxide. You may chemically block the sun, using sunblocks that absorb the sun. The best way to prevent darkening of your skin from the sun, is to use both physical and chemical blocks