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.
Scars (permanent): People who get acne cysts and nodules often see scars when the acne clears. You can prevent these scars. Be sure to see a dermatologist for treatment if you get acne early — between 8 and 12 years old. If someone in your family had acne cysts and nodules, you also should see a dermatologist if you get acne. Treating acne before cysts and nodules appear can prevent scars.