Chest acne into hard bumps consider the possibility of keloid, can be preventative topical medication or the use of laser, injection drug treatment, as follows: 1, prevention: available clindamycin phosphate gel or fusidic acid ointment timely treatment of acne, so as to avoid inflammation for too long, aggravated into hard bumps; 2, treatment: if a keloid has formed, you can choose pulse dye laser to remove red, but also can choose compound betamethasone injection Local closure treatment, but there is a possibility of recurrence. The appearance of keloid can be due to bacterial infection causing inflammation after scar formation, or because the patient is a keloid.