Unfortunately, cleansing your face isn't enough to make acne flee. To battle pimples, you'll need ammunition in the form of over-the-counter or prescription treatments. Benzoyl peroxide (which you get can on prescription from your GP_ kills the bacteria that causes acne, so it's highly effective as a preventative measure. Likewise, salicylic acid can keep pores from clogging.
When that's not enough, a dermatologist can offer help. Oral and topical antibiotics, topical retinoid creams, and chemical peels can all make a difference.