What is an astrigent lotion and when should it be used?

Cleansing. Astringents are used as cleansers for people with oily skin, as in a treatment of acne. Typically they are used after a facial cleanser and before a moisturizer. Using it more than once a day can be overlying drying and remove the face's natural oils, however, so you should only use it when necessary and probably not every day.