After local skin burns, due to tissue destruction and cellular decomposition, a large amount of inflammatory mediators are produced in the body. These inflammatory mediators act on the vascular endothelial cells, destroying the integrity of the vascular structure and increasing the permeability of the blood vessels, leading to extravasation of plasma from the blood vessels. If the exudation reaches the tissue interstices, local swelling is formed, and if the exudation goes under the epidermis, blisters are formed. The inflammatory response after burns is a process with onset, development, and culmination, so sometimes blisters do not develop at the time after a burn, but blisters will appear after 2-3 days. Generally the first 3 days after scalding belong to the exudation period, the exudate is more, and after 3 days, the local exudation gradually decreases, and new blisters rarely appear again.