I started doing kickboxing, I hit the bag and my hand feels loose, I can’t make a tight fist?

The cles last 1 hour and it focuses on boxing movements and punching a 140lb bag. I have to wrap my hands and use 16oz gloves, I’ve noticed that sometimes depending on how I wrap my hands as I hit the bag my hands hurts and the next day it feels loose, I cant make a tight fist, it lasts for about a day or two. Does anyone know why this happens and what is wrong, does it have to do with the hand wrap? What is the medical explanation for this happening?