Hi..for acne and it's marks first thing you need to do is to keep your face oil and dirt  free.Use glycolic or salicylic acid containing face wash twice daily. Apply gel based sunscreen all over the face in morning 15 mins before stepping out.Use clindamycin gel 1% in morning for acne lesions and Adaferin 0.1% gel in night a slight amount over acne and it's marks. Treatment like chemical peels are available which gives very good results in reducing acne and pigmentation..please consult a dermatologist for the same.