teenage shoulder/back acne! HELP

[FraternalBill 0]

Hi i’ve had back/shoulder acne for nearly 3 years now but recently it’s been getting really painful and more irritated. I’m 14, last summer i was prescribed Zineryt lotion which didn’t really help as i thought t spread bacteria so i stopped using it, and since then i’ve been letting it breathe and sometimes putting tea tree or witch hazel toner on the area. My face isn’t clear i normally have a few breakouts on my chin or cheeks. I went to the doctors a couple weeks ago and i’ve now been given Lymecycline hard tablets 408mg a day which helped my face for the first week but i feel like it’s wearing off a bit, has anyone tried Lymecycline tablets? Did they clear your acne? I want to order some Quinoderm antibacterial face wash, is it any good? please reply with some suggestions for my acne X
P.S my shoulders/back has only recently gotten red and irritated. A couple years ago it was only minor