Not being exposed to the sun for a long time may affect the above efficacy.
At the same time, the skin that lacks sunshine for a long time is suddenly exposed to the sun, and the ultraviolet damage will be more than that of normal skin. Therefore, skin with black spots has stronger anti-sunburn ability than white skin.
My advice is: go out for a long time and use high-power sunscreen products, open an umbrella for a short time, don't expose yourself to the sun, and don't deliberately use chemical whitening products ~