I would not have been as calm as you. She is too young to worry about the Teacher's reaction to our anger and disappointment. There is no reason you should not have been contacted. Schools have contacted parents for less. Trust me, if it was my daughter, I would be visiting the head of the department or the principal's office and demanding an explanation.
Forget about the teacher and long term - think about your daughter and someone needs to answer you as to why you were not contacted regarding her injury. How did it happen and when? What is there policy on contacting parents?
I hope this helps. trust me, you will know if your daughter is not be treated fairly in the future. Ask her.