How long to leave breast bondage on

Hello. I’ve been tying my breast with rubber bands for a while now and I was wondering about when I should take them off. What are the red flags and safety time limits? For eg. Because they’re bound so tight, it does burn and after a while the burn is more intense. But then it starts to get itchy. The color changed too but the goal was indeed color change. I’m just worried about permanent damage to my breasts. So what’s the safe time limit and red flags. Thank you!!!!!!