Just want to check, are you having any skin inflammation from
the pimple scar?
It could be the antibiotics prescribed are not really helping to
relieve the scars.
I have a feeling your epidermis layer is inflammed and causing the
sebum buildup to clog up your pores. In addition, your skin could
be irritated by the constant medication that you take.
You could try other therapies like Intense Pulse Light, a kind of
laser to work on the scars but think it's very expensive.
What I can suggest is you can try apply aloe vera like Banana Boat
Aloe Vera Gel which soothes the skin for a start. I used to have
severe pimple problem but no acne and after applying the gel, I
started to see a significant improvement in my skin and even up to
this day, I have a healthy rosy complexion 
