Hello. Thank you for writing to us at healthcaremagic Acne can break out on chest, back, shoulders and face etc. All these areas are rich in sebaceous glands. Acne breakout happen even otherwise and fairly commonly in general population and is not something that suggest HIV. Moreover, since you have already tested negative for HIV so there is no question worrying about HIV. I suggest that you see a dermatologist for reassurance and for the needful. A severe acne breakout on torso and face may require a course of an Oral antibiotic e.g doxycycline or minocycline for a few weeks. Topical treatment is an adjuvant to oral treatment and includes antiacne antibacterials like benzoyl peroxide/ clindamycin gel. Regards