How can you tell when pityriasis rosea is healing?

Rash lightens: The spots will flatten, the redness will become paler and individual lesions will disappear.

Pityriasis Rosacea: Symptoms most often last 4 - 8 weeks. Symptoms may disappear by 3 weeks or last as long as 12 weeks. The rash starts with a single large patch called a herald patch. After several days, more skin rashes will appear on the chest, back, arms, and legs.