I've been on Erythromycin for a month and about 2 weeks. Does erythromycin actually clear up acne and how long does it it? 70% of my bacne is covered with acne and just the middle of my chest is. Btw what is cyst acne exactly? I still have under 3 months of erythromycin left but I feel like it's not really working and i'm wondering if i should just get a referral to a dermatologist and maybe get on Accutane.