Blisters commonly form as a result of pressure and injury thus protecting the affected spot from further damage. They occur especially if the burn affects the capillaries in the burn area.
Blisters caused by burns may need medical attention so one should consider visiting a doctor, as stated by the Better Health Channel. They are usually filled with a clear fluid and have a tender skin patch. It is advisable not to burst the blister as it may lead to infection. If it is necessary to burst the blister, one should first clean the spot with soap and the prick the blister with a heated needle.