You wake up. You wash your face. You put on sunscreen to protect your skin. But by lunch time, your face looks shiny. By evening, you see new small bumps. This is frustrating.
Many sunscreens that you buy from the store have oils. They have fake smells. They have ingredients that block your skin pores. When your pores get blocked, you get acne. This is true even for sunscreens that say they are for the face.
If you have oily skin, your face already makes more oil than it needs. Adding a heavy sunscreen makes the problem worse. That is why you need to switch to a mineral sunscreen for oily acne prone skin.