Did you harvest, or just remove the bud rot cola? And if you continued the grow what was the humidity at? I got bud rot on my last grow 3-4 weeks before the grow would've finished. Rest of the week was forecast for 85% humidity so I chopped, but have always wondered if I'd let them grow a little longer how they'd have fared.
I just removed the rotted cola, and left the remaining stem intact, so far the buds are doing well, and show no sign of decay, in fact, im starting to see new growth development on the buds, so they were stunted due to the stress, but looks like the remaining buds will be a nice little yield.
I did cut open the decayed bud, hoping not to find a parasite or something that would cause it to literally die during a 12 hr period, but im still stumped as all 3 plants in this grow room are doing well, including the plant with the rotted cola..
fingers crossed, i still have about 2-3 weeks to go...