Korean double cleansing - is it necessary and how to do it right?

Double cleansing (an oil/balm cleanser first, then a water-based cleanser) is mainly worth it when you wear sunscreen and makeup — exactly your case — because oil cleansers dissolve SPF and sebum that water-based cleansers leave behind. On bare-skin or no-SPF days it is optional. For oily, acne-prone skin, a lightweight oil cleanser that emulsifies fully and rinses clean is unlikely to break you out; look for non-comedogenic formulas and rinse thoroughly. A gentle low-pH gel cleanser is the best second step (foams can be fine if not stripping; avoid harsh high-pH bar-type cleansers). The goal is clean-but-not-tight skin — if your face feels squeaky or stings, the routine is too aggressive.

This is general information — an in-person consultation with a board-certified specialist is the only way to get advice tailored to your anatomy and goals.