How can I treat a bad pimple fast?

Hot compresses. Some acne lesions are large, ugly, and may be painful. You can try to treat it at home by yourself, with hot towel compresses and by rubbing a Benzoyl Peroxide Gel into the spot several times a day. You can buy this without a prescription. If it is not better, and you have a special event to go to, you must visit a dermatologist who can give you an injection of kenalog (triamcinolone) right into the bump.
Good question. A pustule from an acne lesion is unsightly and at times painful and one has the urge to do something, especially if a social event looms. Scrubbing with soap and water and cleaning with alcohol with good clean hands and a sterile needle, one can often gently pierce the head of the pimple and using a gauze or cloth, gently express it. Then apply alcohol, witch hazel or astringent and use ice pack.