After the spanking it is very important that you comfort her, don’t just leave her alone crying. This is her most vulnerable time and she needs you. Even if you’re upset (which you should not be) take the time to hold her and ensure her that she is forgiven. Once she has calmed down, possibly after corner time you can ask her why she got the spanking to ensure that she understands what the problem was and what to do next time to avoid punishment. This is a good time to allow her to talk as well, she may disagree on why she was punished and should allow her to explain her side of it. There may be a miscommunication or misunderstanding so allowing her to share her side of it without fear of further punishment or argument will strengthen and build a loving relationship. After she is had the chance to explain consider the punishment over, if you agree with her explanation or not, let it go and go on with your life.