Head and shoulders classic is indeed pretty good for body acne.
Have you tried supplementing with vitamin d3? Take 1000iu of vitamin d3 per 25lbs of body weight. Take every morning when you wake up. If it works for you, within a week you should start to notice no new or dramatically less new active pimples, and a massive calming or complete end to inflammation and an acceleration of healing.
If you start taking d3 and you notice any anxiety, muscle twitches, or more difficulty having a bowel movement, start taking 600mg of magnesium every night before bed.