Answer:
The dermis and epidermis must have been affected.
The dermis formed the outermost layer of the skin. it is made up of layers of stratified squamous epithelium cells,(group of tough flat cells) which separate and protect the skin from external environment. The cells of the upper epidermis are non-living and fragile in structure, since they lack a direct blood supply; therefore it is easier for them to form broken blisters when exposed to tension or heat as experienced in the question. The older cells are usually remove or washed away and replaced before the lower cells are exposed.
Therefore the blisters is from the epidermis.(upper).Cells of lower epidermis or subepidermis have high tenser strength are not easily broken, therefore the blisters can not be from this part.
The dermis is the living part of the skin it is made up of blood vessels, nerves (sensitive to temperature change), and sweat glands. it is separated from the epidermis by the basement membrane.
It is the inflammation of these nerves which synapse with receptors sensitive to temperature, pressure, tactile simulations,that resulted to pain experienced by the individual in the question.
Since the cells of the dermis are well innervated the sensation of pain and heat must have been received by the pain receptors in the dermis.