First you need to make sure that you use plenty of sunscreen in the future. Protect your burn with sunscreen too. Next you will need to apply medicated aloe vera gel and avoid hot water.
Rinse off in a cool bath. Take some tylenol or other pain reliever if you are experiencing pain. You can also apply a skin soother to relieve the symptoms. Aloe Vera works well in soothing and healing.
Leave the blisters intact. They are your body's way of protecting the skin underneath and protects from infection. Use a good quality lotion on the area three to four times per day and allow the area to be open to the air while at home. When out, wear loose fitting clothes until the area begins to heal.
A blistering sunburn probably should be treated by a doctor because it's just what it's called, a burn.There are many sunburn sprays on the market you could try because you probably don't want cream rubbed into the burn.
Keep the area clean and apply antibacterial ointment. IF you are going to lance blisters, do it with a sterile needle. Let area dry, but keep it covered if under clothes.
