Symptoms of the rash in polymorphous light eruption may include: Dense clusters of small bumps and blisters Inflamed, raised rough patches Itching or burning People may rarely have other symptoms such as fever and chills. In polymorphous light eruption, eruption refers to the rash, which usually appears 30 minutes to several hours after sun exposure. The rash usually appears on areas of the body that are covered during winter but exposed in summer such as the upper chest, front of the neck and arms.