Whether the skin is oily, dry or normal, sun protection should be used daily by everyone.
When it comes to oily/acne-prone skin types, it can be presumed that moisturizers with SPF are not required. This is usually a misconception. Sun protection lotion for acne-prone and oily skin should be oil free and water based. This way it would not clog the pores and provide sufficient protection against sun damage.
SPF should also be reapplied after excessive sweating, swimming and after 80 minutes of being in the sun. The SPF lotion itself should also contain anti-oxidant ingredients to protect the skin from free radicals. Acne-prone skin especially needs to be protected from the sun as it can worsen the acne. It may produce more oil, cause more breakouts and hyperpigmentation which can leave scars.
Whether the skin is porcelain or blemished, sun protection is always a priority.