Serum to reduce acne marks within two hours of application | Do you have an appointment in a few hours, but your skin isn't looking its best? Kiehl's Dermatologist Solutions Truly Targeted Blemish-Clearing Solution uses... una Intelligent liquid patch technology that helps improve skin's appearance with visible results as early as 2 hours after application. The concentrated formula with salicylic acid, niacinamide, and licorice extract not only targets active blemishes but also reduces post-acne discoloration.