Firstly, you should ensure that you treat the whole area where the acne occurs, not just the spots themselves. Secondly, it can take approximately 4 months for acne treatments to be fully effective so you may not see see immediate improvement in your condition, especially within the first 4 weeks.
Topical treatment is preventative in that it helps to stop lesions from developing rather than getting rid of the spots you already have. You should treat the whole acne-prone area, not just individual spots, to get the most out of your treatment.