Sunscreen is one of several new items that have been added to PEAK as part of the Mesa update, and it's tied with unlocking a new badge.
This item is very important if you want to survive the harsh nature of the Mesa biome. This biome's main threat is the harsh temperature, especially during the daytime. Sunscreen is an effective way to block out the sun's rays, and might also be essential if you want to complete the Cool Cucumber Badge.
