A burn is damage to your body's tissues caused by heat, chemicals, electricity, sunlight or radiation. Scalds from hot liquids and steam, building fires and flammable liquids and gases are the most common causes of burns. Another kind is an inhalation injury, caused by breathing smoke.
There are three types of burns:
Burns can cause swelling, blistering, scarring and, in serious cases, shock and even death. They also can lead to infections because they damage your skin's protective barrier. Antibiotic creams can prevent or treat infections. After a third-degree burn, you need skin or synthetic grafts to cover exposed tissue and encourage new skin to grow. First- and second-degree burns usually heal without grafts.
NIH: National Institute of General Medical Sciences