Nice looking bud there. You gotta get rid of mold. You could try spraying a fungicide all over it, but if it were getting close to harvest, I would make sure it is an all organic fungicide. If this doesn't work you have to perform surgery. You cannot smoke mold or rot, it is very dangerous. I live in the Pacific Northwest, and have to trade in proper yield for some bud rot on anything I grow outdoors. You just gotta keep picking out the rot, and think about harvesting early.