You have developed photopigmentation.
First thing that you should do is to prevent further photodamage. This can be done by wrapping cloth over the face or by using broad spectrum sunscreen. Oral photoprotective drugs can also be taken.
Moisturizer will not play any role in photopigmentation.
Already developed pigmentation can be treated by demelanising agents as advised by a dermatologist
MD - Skin & VD