Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain dark or black spots left on face after pimples seems to be due to Post Inflammatory Hyperpigmentation that occurs due to inflammation and infection caused during pimples.. As far as using Kojivit is concerned it is Kojic acid containing cream and is a mushroom extract and safer depigmentation formula.. It can be used at night, however you can also apply it during day as it has no deleterious effects on sun exposure.. Along with it you can also use additional repigmentation products for faster resolution of pigmentation like wash your face with Salicylic acid and glycolic acid containing facewash. Glycolic acid and arbutin containing creams are also helpful.. Vitamin E gel can be applied at night. Azelic acid preparations are helpful.. Exfoliate your face twice a week to unclog the pores and remove dead skin.. You can also apply a sunscreen lotion when exposed to sun.. . You can also go for treatment like Microdermabrasion and chemical peeling.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.