Danny, as Z said, the diagnosis is important. Where are you getting the acne? What is your diet comprised of mainly? And what age range do you come under?
In my experience, hormonal changes with a messed up diet created the majority of skin conditions. Eating a lot of junk, rich, carby foods can create heat in your system which can manifest as acne. It can also indirectly contribute to (an existing) hormonal imbalance which again can make you break out.
There are different types of acne depending on severity too, being aware of this will help you determine the cause. If you have cystic acne, build up of toxicity (mental, environmental or dietry) can be a culprit whereas less severe forms can usually just come about from a more minor change or could be hygiene related. It really is more complex than just one thing usually.