No way you'll be able to get that back on the plant.
It's pretty far into flower, but it may clone and then reveg.
Cut all the leaves/buds off the lower end, so you have the top bud and maybe 1 bud/node below it. Make a clean slice 3-4 nodes down from there to take off that dead end that broke and plunk it into a cloner.
Don't forget to trim about 50% of all the leaves remaining and don't give it a ton of light(doesn't need to produce food, it needs to cannibalize itself to create roots). The more oxygen you can get into the water it's in, the better (fish tank bubbler works for me).
Mine usually take about 2 weeks to form roots enough to pot. I rarely take cuttings past 2 weeks into flower though.
Good luck!
