Suggest Treatment For Chest And Back Acne

I have serious chest acne + some Back acne
I visited a Dermatologist, he gave me
1 CLINDAMYCIN PHOSPHATE GEL- CLEARGEL + ADAPALENE GEL -APGEL(Both of the Gel to mix and apply on my chest)
2. Azithromycin Tablets- CADZITH 500( For 20 Days course)
Already 10 days has past but there is hardly any improvement on my acne moreover it is spreading and taking pigmentation over my chest.

Previously before visiting this Doctor I visited another doctor he prescribed me with
1.Afderm-MX( ofloxacin, ornidazole, terbinafine & clobetasol cream)
2. CNN 50 ( Minocycline Hydrochloride Tablets)
3 Multivite Gold

My Present Doctor told me to stop using Afderm-MX as it is the reason for the acne to grow so much but I can continue with CNN 50 and the vitamin tablets and to use all the present medicines he had given, but really 10 days have passed and I am really confused why my acnes are not going away neither it is reducing( I have stopped using AFderm-MX 10 days before).The Chest acnes are recent before 10 to 15 days I got them but I am suffering from back acne from 6 to 7 months. But now the Chest acnes are really have become very serious and the back acnes are not so much there just the back spots and few acnes.
Have I been Diagnosed Correctly ? or can us help me to provide me with some better medicines so it reduces quickly and the pigmentation goes away after the acnes are completely removed.