@hempkid STOP advising if you are blind !!!!
It's MOLD, very bad for inhaling in any matter.
Take plastic bag and cover infected part, cut a lot lower and dispose it far from grow space.
It's multiply by spors and air.
Bud Rot . Always a lost battle. First hours you don't see anything, then on 6th hour - white fuss, later it goes brown/grey . Never use such weed.
Check YouTube for hydrogen peroxide, soda, lemon acid bath for weed before harvest. If you need any more info - p.m. me here. They have chat in left bottom corner.