I think its better to forget the whole unfortunate episode. Certainly, there is no reason to bring it up now.
Make sure that child abuse is prevented in the future and that she knows that when someone touches her she should stop him/her and also report it immediately. This should be part of advice to all young children, not only to girls but boys too.
Under normal circumstances she will not ask you about a forgotten trauma. My own feeling is for you to just drop the matter altogether.