This is shoulder acne. I have tried letting benzoyl peroxide sit like a mask on it. I have exfoliated it with mud, salicylic acid, and lactic acid masks, I have tried anti-fungal. I have used antimicrobial washes. I have rosacea so I tried that treatment. I take allergy pills daily. It will all but calm down and in a day twenty new little pimples are there. 