Besides the possible side effects (I don't suffer much of them, but I know I'm lucky), you should also think about what you will do if it does work perfectly and her skin gets much better. I have been using Neotigason since I was twelve years old and I still know how bad my skin was before I started using Neotigason. Now i'm 26, and when thinking about having children the whole hereditary story is an issue, but the thought of having to stop using neotigason for at least three years (before getting pregnant and during pregnancy) is a really big factor too.
Although I am very satisfied with the effect neotigason has on my skin, it is not a light decision to make!
I agree with Keith and Beth that two years old is much to young. Neotigason should only be an option if everything else fails and even then...

P.S. You will find more discussions about Neotigason on the Retinoids Forum. In the United States Neotigason is called Soriatane.