bud rot. NOOOOOOO !!!!
I feel for ya...
Remove all affected areas, get a rot stop spray if its not too late in flower (there are some non systemic all natural ones).
Isolate affected plants and cut early if you have to. Clean everything with something fairly heavy duty.
Get more fans or watch your humidity closer.
It happened to me I took precautions and its never happened since.
Wishing you a happy and healthy recovery.
Mouse