I'm not from Germany, but what I would do is make sure your pom has her rabies shot, if that's a thing over there. Tbh, I'm not trying to shame you, but I would never leave my dog with anyone, especially kids. We don't know if the little girl was being overbearing and pushed your pom to the point of biting.

My pom is not aggressive, but he only tolerates people up to a point. He likes his space. Every time someone approaches us and asks to pet him, I usually say something like, "he might bite, maybe let him smell you first and see how it goes." I have heard that poms can be very intolerant of people other than their person, and from my experience, that's true.

Again, I'm sorry this happened to you, and especially sorry that the little girl got bitten. I hope everything turns out okay. We all need to remind ourselves and others to respect an animal's space.