Final answer:
A burn area with no pain is most likely a full thickness burn injury, which includes third-degree and fourth-degree burns, due to the destruction of nerve endings.
Step-by-step explanation:
An area of burned tissue that is not painful is most likely a full thickness burn injury, also known as a third-degree burn or a fourth-degree burn. These burns extend through the entire epidermis and dermis and can also damage underlying muscle and bone. Since the nerve endings are destroyed, there is often an absence of pain. However, this type of burn is serious and requires immediate medical attention for proper healing and recovery.