I was adjusting one of my tie downs and must have pulled down on it too hard I didn't even notice I did it. The thing is is I only had like 10 minutes before lights out so I hurried up and untied all the branches so I can get it back together and then took that rubber coated green garden wire the soft kind and just wrapped it really tightly around it and then put a zip tie over that and zip tied it tight and left all the branches untied until morning because I ran out of time. That plant was looking nice too I'm pissed. I'm going to have to doctor it up in the morning. I wish I could just drip some rooting hormone in there and it would just heal back together.
If its a serious break, i would be much more concerned with making sure you fix it enough to stay alive than if youre in the room with lights off right now. A few minutes with a flashlight or even the light back on momentarily literally
one time isnt the end of the world. If youre really worried put an all green screen on your phone and use that as the light source, green light doesnt interrupt flowering
duct tape it back into place, and drip superglue in the open crack. It will heal stronger than before within a day. I always keep this stuff in my weed plant first aid kit