Hello im 18 years old and have a problem..

I have back acne now I think for almost 8 months. The last months it is getting worse. The biggest problem is that old pimples are very red and do not go away. There are also new. 2 days ago I started the Apple cider vinegar tonic, it seems like the pustules stand out right now but I don't know if this is the intention. Is the first time bad and then good like an healing breakout? I'm going on 3 weeks on vacation to a warm country and shame on me so much.. I drink 3 liters of water per day and eat pretty healthy. I also die head and shoulders on my back in the shower for 3 weeks. I drink alcohol every Saturday night. Incidentally, I have in me face no suffer from acne it's really only me back! Does anyone know If im doing good? I hope Some of you response. And btw is this really bad acne that i has or im i al little bit Lucky and goes al the acne gone by the sun in the warm country?

dont blame me for my english, and its my first post ever