I'm planning to do some late night icy mischief
Who is the icy mischief going to be directed towards?
I'm going to do something to get back at these bitches who just hate me.
You may want to get back at girls that hate you, but taking revenge on them in the dead of night only continues the cycle of hatred. Just forgive them for whatever they've done and move on.
There is no need to forgive them. I hate them.
Perhaps that was a bad choice of words.  You don't need to accept that what they have done to you is okay, but I don't think that you should perpetuate this cycle of revenge against them, as that will just cause more problems.  Instead of lowering yourself to their level, just forget about them and move on.