Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain it seems that you have pimples over face since a month that us going on increasing in size and no improvement with Tretinoin cream that is a retinoid.. Well, pimples can occur due to causes like : -Clogged pores. -Oily skin. -Hormonal Imbalances. -Bacterial infection. -Inflammation -Excess sun exposure etc. On the other hands dark or black spots left on face seems to be due to Post Inflammatory Hyperpigmentation that occurs due to pimples.. You need a combination of anti-acne and antibiotic treatment along with dietary and lifestyle modifications.. You should consult a Dermatologist and get evaluated and he can advise you to wash your face with Salicylic acid containing facewash.. Apply topical ointment containing Clindamycin and Benzoyl Peroxide.. Apply retinoids like Adapelene gel in thin layer on pimples at night time.. Do cool compresses over face.. 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.. Oral Medication like antibiotics like Clindamycin or Minocycline and retinoid like Isotretinoin can also be advised Avoid oily food.. For dark spots apply creams containing Kojic acid, glycolic acid and arbutin.. Vitamin E gel can be applied at night. Azelic acid preparations are helpful.. You can also go for treatment like Microdermabrasion and chemical peeling.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.