I have had acne for like 8 and a half years.I thought i would never get clear(iwon't get emotional, i'm done with this shit all these years about my face).I was reading an article threemonths ago that dairy can cause acne. So i freaking stopped. And guess what. yea..i got cleared up.no more cystic no more big spots.It's full of hormones that is why it can cause the acne.
Just try to cut dairy off.I'm sure you will see a HUGE difference on your face.And i'm not talking only for milk,yogart, greek yogart,cheese, i'm talking everything thatcontains any type of dairy.
Of course i get a couple spots(probably because of the man needs, if your know what i mean;) just because it mess with the hormones but i'm trying to cut it off as well) here and there sometimes and still got the scars but no more acne.
Dairy triggers my acne.It may not triggering yours but for many it sure do!
Pro tip: If you're using a spot lotion...just put it all over your face and not only on the pimples. doing this it will l prevent break out on the other areas of your skin.Does that make sence? I hope it does because it help me alot!
Now I can drink a gallon in a day and I won't breakout because of it, but that probably isn't in my best interest. 
Food does not cause acne but there are a number of complex effects it has on our biology that effect things like inflammation and insulin in our bodies. I think a certain diet can alleviate or worsen symptoms of acne honestly.
I am 26 and have had severe acne for 16 years (though not so "severe" anymore) and I did not experience acne flares from dairy. I was not a "milk drinker" type as a teen or adult. My "demon food" for acne flares is potatoes and pasta but unfortunately those are actually my favorite foods to eat lol.