The time for drug rash to recover on its own should be objectively analyzed based on the severity of the drug damage and the body’s own ability to repair. First, if the patient is in good health and has strong repair ability, the dose of allergic drugs is less, and the patient has a less extensive and less severe drug rash, the drug rash can subside on its own after 7 days; second, if the patient is older, has more combined underlying diseases, takes a larger dose of allergic drugs, and has an extensive drug rash with obvious redness, swelling, pain and other symptoms, the patient The drug rash tends to subside more slowly, and some patients even need 1-3 weeks to subside on their own.