In severe sunburns, your skin may blister and swell. The blisters are filled with liquid. While it might be tempting to pop your sun blisters, try not to do so. The blisters form to protect your skin and the liquid inside them is there to help heal your burned skin. Therefore, it's best to let the blisters run their course and go away naturally. If a blister accidently pops, do your best to keep the affected area clean, which will stave off infection.Use a sunscreen and wear protective clothing to safeguard your skin from the sun's harmful rays.