Hello, There can be discomfort with tooth movement. Your daughter may bite differently and put temporary additional biting pressure on certain teeth. I suggest advising the orthodontist of her discomfort. Try some antiinflammitory medication such as Tylenol or Advil. If she does not feel better, make sure to have an exam and X-ray if needed to rule out a tooth problem such as an abscess. Thank you for your inquiry. Stress can add to this as well.