For UVA protection, a sunscreen with a high UVA protection of PA+++ or higher of PA++++ as recommended, especially to treat PIE. PPD is the UVA equivalent of SPF; use a sunscreen with a minimum of PPD20. The PA+ system has a + that corresponds to a tier of PPD protection. Of note, different countries use different PA systems. Japan and Taiwan changed their PA system to a 4+ tier system while Korea uses a 3+ tier system.
Unwashed sheets and pillowcases lead to cross contamination which leads to pimples. Aim to wash your bedding once or twice a week to prevent bacteria from building up and affecting your complexion, suggests Dr. Papantoniou. If that seems overboard, at least aim to wash your pillowcase once a week since that's where your face rests while you snooze (and dream of flawless skin).
Drugs: Some medications may cause or worsen acne, such as those containing iodides, bromides, or oral or injected steroids (either the medically prescribed prednisone [Deltasone, Orasone, Prednicen-M, Liquid Pred] or the steroids that bodybuilders or athletes sometimes take). Other drugs that can cause or aggravate acne are anticonvulsant medications and lithium (Eskalith, Lithobid). Most cases of acne, however, are not drug related.