Sunburn is the way that the body reacts to severe damage. As the topmost layer of skin has been damaged by too much UV radiation, the body sheds this layer to prevent those damaged cells from causing new problems (such as continued and unregulated growth caused by mutations induced by the UV radiation that could ultimately end up causing cancer). Depending on the amount of damage, there can be a local reaction as well which can cause some increased fluid and infection fighting cells that go to the area, which can create the pus that forms in the blisters you are seeing. The sloughing of so much skin can be painful due to the damage that is induced to nerve endings as well. Moisture, as with aloe vera extract, can be very soothing, and helps to prevent further damage by keeping moisture in. Because the skin has been traumatized to such a great degree, there is a somewhat increased risk of infection, however this risk should not be increased by using aloe vera gel or other common skin remedies. If the pain continues, your skin is overly damaged, or you have other concerns, please speak with your doctor
. And, please, use more sunscreen and avoid such prolonged exposure.