Everyone has the required amounts of vata, pitta and kapha, even a "pure" pitta type has vata forces or they wouldn't be alive!
So it's silly to get hung up on what type you are, instead you should see what you have and then try to balance it. Acne is seen as a "heat" imbalance, pittas tend to suffer from burning issues, heart burn, abcesses, acidity, etc.
Imagine a pitta type (or imbalance) thru its life cycle
1. bile is very good and releases very well
You can eat ANYTHING! you don't suffer from any problems and you can eat alot and not even put on any weight! The bile is mixed with food coming out of the stomach, the result is completely alkaline mixture which completely cleans out the intestines and properly absorbed. The bile quality is good, so when its recycled, the liver has relatively short job detoxing the bile (since its mix with food + intestines)
However after a while, bile can't be reused and so its created from the diet, the diet is poor in racid fats, unstable fats, so your health starts to suffer.
The poor quality bile may not flow out of the liver, it may become "sticky" and this will start to turn into stones once bacteria find their way to that mess.
2. bile release is poor, bile quality is poor
The liver is now tired because of stones created, the bile quality is poor because the bile recycle is poor and blocked up. The food isn't absorbed as well, everything suffers.
The bile is transported back to the liver, via the blood, the toxins that aren't removed by the liver, end up in your skin..
OR, they don't! if you have alot of protein in your tissues, the toxic waste ends up in your joints, this causes painful Arthritis conditions because the waste is then attacked by bacteria. The skin filled protein is red, puffy, sore and it looks like rosacea if on the face.
3. bile release is very poor, bile quality is ACIDIC!
The food now burns the entire digestive tract, you get IBS, blood stools, gas.. bacteria overgrowth, candida, etc.. candida causes even more toxic blood and stones, the friendly bacteria can't survive in acidic waste, so die.. food for other bacteria.
Pittas tend to suffer from vata imbalances once pitta is imbalanced because the bile is needed to keep vata going, then when toxic overload hits, you get kapha imbalances such as coughs, colds, flu, pneumonia because mucus is trying to wrap around toxic waste.
Once the blood is poor and the liver is giving up, the kidneys will try and remove what it can, this leads to problems in the lungs, because the lung and kidneys are linked, waste NOT removed by the kidneys CAN end up in the lung tissue and vice versa.. (see any heavy pneumonia patient in ICU ward)