hi, I am also lactose intolerant and have experience in dealing with this. If your body is unable to cope with challenging foods such as stimulants (caffeine etc), animal foods, and probably fatty foods too, this may mean that your digestion is quite weak. I also had acne for years and I know that if I eat any of these types of food, my skin will erupt. I have found that the best method is to eat a gentle diet based on the foods that chacha mentioned. It's ok to cut down on protein for a short while. There's actually quite a lot of protein in grains and vegetables such as broccoli. If you combine something like chickpeas and rice, you get more protein than in meat. Mushrooms are a good food to combine with grains as they also form proteins.
Drink lots of water to get the toxins out of your body, aloe vera is also good to support healing of the digestive system. (basically the digestive system is weak, is unable to process challenging foods, this puts strain on the liver- which deposits toxins in the blood which pop up as acne)

I know someone who is also lactose intolerant, and he mixed live yoghurt with water to make a drink, which when taken on a daily basis in small doses desensitised his system to the lactose. You couold try that. And if you give in to temptation or unknowingly eat something with dairy in, take arsenicum 6 which could act as an antidote. Don't rely on this though!

If you want anymore advide please email me, I have lots of info on this matter having been through the whole thing myself!

nic x