Hormones for sure, definitely not from the whey.
Im 19 now, when should my hormones be balanced? 20-21? I know you can get them at any age but i got acne 4-5 years on my back now

feelsbad cant even take my shirt off
If you are having acne problems go to a doctor to solve it, I've had them since I was 11 or 12, barely remember when I started, my worst time was when I was 16-17 but that didn't stop me from having fun or taking my shirt off, it's something normal but if you don't feel like taking your shirt of because of them definitly go to a doctor, sometimes they won't be able to solve the problem completely.
On topic, whey does not produce acne, it's like the myth of eating chocolate, and of course your genetics, some people do tend to produce acne from different foods and some don't