so my face is pretty ok-ish. It doesnt develop much acne anymore. I use secret aztec indian healing clay for it.

But... My back. The acne on my back just doesnt react to nothing. I tried using acv topically and consuming it but it didnt work. The acne in my back isnt bumpy its smooth but dark coloured, scars? There are some acne which are 'bumpy' but alot of the crap on my back is like a scarred, in which case it is like dark red blobs that have merged with my skin

What is a good treatment for this?

It is currently summer and during work i do get sweaty but i have no choice but to continue (health and safety hazard). What can i apply topically or orally to get rid of this evil?

Thank you