Final answer:
A burn that presents with significant pain and blistering is most likely to be classified as a deep partial-thickness burn, which extends into the epidermis and dermis.
Step-by-step explanation:
A burn that presents with significant pain and blistering is most likely to be classified as a deep partial-thickness burn. Deep partial-thickness burns extend into the epidermis and dermis, causing tissue destruction and affecting the nerve endings and sensory function. These burns require medical attention and heal slowly without it. Full-thickness burns, which affect the underlying muscle and bone, are even more severe.