Final answer:
The burn described, affecting deeper than 1/3 of the dermis, painful, with red/white coloring and moderate edema, is a third-degree burn requiring medical attention.
Step-by-step explanation:
A burn that affects the epidermis deeper than 1/3 of the dermis, is painful with red/white coloring, and has moderate edema, with blisters being rare, is most likely a third-degree burn. This type of burn fully extends into both the epidermis and dermis, destroying the tissue and affecting the nerve endings and sensory function. Such burns are serious and typically require medical attention as they heal very slowly and can lead to significant complications if not properly treated.