I have lived with acne for a longtime, and have researched a lot... Here's what I know:
Because acne is typically caused by one of two things (food allergy and/or hormones), the over the counter "treatment" typically involves dealing with the symptoms. Dermatology usually recommends a gentle face wash and/or a chemical or drug treatment. A third reason (in conjunction with regular acne) is pores become clogged from makeup (which often is used to cover up acne which can make it worse anyways...) THere are thousands of products out there--a lot of improvements since stridex pads came out when I was a teenager

First, figure out the type of skin your daughter has right now... sensitive, oily, combo, dry, etc. And figure out what kind of acne is she getting (blackheads, whiteheads, boils, etc.); this will determine what kind of "treatment" you will need... Be aware a lot of acne products are too harsh and can OVERDRY skin which makes it even oilier (the outer layer of skin actually gets drier but the folicles pump out more oil to compensate for the loss), which leads to more pimples for some.
So if your daughter is just having a few pimples, then a spot treatment might work better rather than using a treatment facewash for her entire face kwim??
Spot Treatment Suggestions: Put a dot of mud mask or toothpaste on the pimple to dry it out.... there are plenty of home remedies which are very inexpensive and work well (see a book suggestion below). While $$ sometimes indicates better products, it's not always the case for acne treatment products... I've used (successfully) Sonya Dakar Drying Potion (it's about $25, and is the only thing that works for me).
Also consider that things like hair and hands touching the face can add bacteria and oil to the face... which can lead to inflamed hair follicles.
If you and your dh experienced bad acne in your teens, then you know the importance of teaching your daughter proper care... like not popping a pimple or keeping hands away from the face. Consider getting her tested for allergies... I found that if I eat pistachios that my face gets a few oily/watery pimples. IMO Since she is still pretty young, you could probably wait to start a specific cleansing routine... like the proactiv that was recommended. Even just using a wash cloth or splashing water on the face is a great way to clean it.
A warning: the industry is filled with many products with products that don't and can't keep their promise. In addition to suggestions above, I would strongly recommend trying to use some home rememdies before spending lots of $$$ on the products. There are several books that you could check out at the library or buy used that may help. One that I just got this summer: "naturally Healthy SKin" by Stephanie Tourles. I haven't read the entire thing, but they are simple, and logical suggestions IMO. I've tried everything from drug store Noxema to Stridex to Mary Kay to expensive Sothys to Sonya Dakar to Phytomer... and still searching.
Things that did work for me: cutting out dairy (I drink soy, also because dairy gives me migraines), and using a gentle/moisturizing cleansing wash and lotion. Also, I bought a steamer... (a bowl of boiling water worked too) when I was using it often it did help clear things up (put my head over the steam with a towel over my head). the steam causes the pores to sweat which eliminates the sebum from the pore (in theory). Of course I'm neither an esthetician nor a dermatologist. But hope that helps.