Hello,My 2 year-old daughter has a hard bump on the bone behind her ear. I would say it is about the width of a nickle, and sticks out about the width of my pinky finger. It is hard and has no give to it. It also seems to be painful if it is touched. As far as I can recall, it was not there this morning. Should I be taking my daughter to the ER, or wait to see what happens?Thank you.Colleen