Final answer:
A burn that is painful, red, with no edema, similar to sunburn or flash burns, is a first-degree burn, which affects only the epidermis and typically heals on its own.
Step-by-step explanation:
The type of burn described as being painful, red, with no edema, similar to sunburn or flash burns, is a first-degree burn.
First-degree burns affect only the outer layer of the skin, known as the epidermis, and do not involve the deeper layers such as the dermis or subcutaneous tissue. They can be quite painful and may cause redness and swelling, but they usually heal on their own within a few days. The most common example of a first-degree burn is a mild sunburn.