I have had acne for as long as I remember and still get it even now. I find the Neutrogena range of products the only thing that works for me. They contain salicyclic (sp?) acid which I find helps. They even have a Anti-Wrinkle, Anti-Blemish cream for us oldies with spots and crows feet!!
You can get Neutrogena in supermarkets and chemists and they are not that expensive, think around $10 or $15 a product..

Just a caution on tea tree oil, Soul, dont use the oil straight on her skin undiluted as some people (myself included) get contact dermatitis from it.

Hope that helps Chloe-Mae.