It takes a long time to apply it. Generally, it is enough to apply 15- 20 minutes before going to bed, 2-3 times a week. Potatoes are light-sensitive foods, so they can't be exposed to the sun after smearing. After application, wash off the residual sugar and starch on your face with warm water, then wash your face with cold water to shrink pores. This is not easy to cause allergies, and it will play its role.