Pytiriasis Rosea & back acne

I used to have a perfect skin, never had I encountered with skin issues (other than sensitive and sometimes dry skin on my legs). Last year September, I discovered this herald patch near my breast. Concurrently my back developed some acne-looking "acnes". I went to see a dermatologist and I was diagnosed with Pityriasis Rosea (PR). Though no meds that can cure PR, she prescribed me some antibiotics (to "kill" the virus), and hydrocortisone lotion, & some anti-itch tablets. She assured me that those "acnes" on my back are not acnes, and will go away as the rashes disappear.

A few weeks later, the rashes are gone, but the acnes stay. It has been more than 6 months, and the acnes are still there. There might become lesser at times, and break out most of the times!! I am on and off some drugs such as Xenical (rare occasions), Phentermine (30mg / 15mg) and Mediaxal (Benfluorex Hydrochloride 150 mg). These drugs had never given me these acne problems before I was diagnosed with PR.

I can't wear clothing that reveals my back (which is painful under such humidity), I can't go for swimming due to the fear of embarrassment, and I would refrain from having back massages due to the fear of aggravation. Any advises would be greatly appreciated. Thank you.