You aren't in the best situation but it is what it is. When I have run into bud rot, I would cut out a good amount of healthy tissue around the diseased area. There's always more to the infection than what you can see. If you cut out more healthy tissue, you will slow it down a bit. However, once its infected its hard to get rid of it no matter what you do.
By the way, what happened is because of your humid weather. Those colder nights hitting the dew point. Keeping them dry at this stage should be your #1 priority. As for this crop and cutting early? That's your call. I'm going to guess they've been flowering 6 weeks at most and are still a couple of weeks from maturity.
Next year, look into some of the high THC auto-flowers. If you start them in May, you'll be harvesting them in August. You'll beat the fall weather.