I messed up.

Yes, he is right this is bud rot, or Botrytis, it is a fungus. When is had infected and entire top like that is likely a good portion of the plant is affected. Sometimes you can salvage some of the grow but i would dry it first and open up the buds to see if you see any more mold,and once its dried if it is not good it all just going to start to mold,and if not once dry and you cure it and still not mld. id say it is okay. but it can start in the roots from overwatering and be systemic in the plant and the buds can rot away. Also can happen from having really dense buds and condensation forming o the stem. is usually starts from inside so its hard to spot before its too late. so prevention of mold is key. sometimes some plants like to mold more than others as well so genetics plays a role as well. but the most important thing is your environment and not big swings in humity and temperature. and knowing what the dew points are relative to your environment. cold nights can be bad because thatswhen you can get some condensation. beloved 62 degrees or so. I would harvest anything you think is remotely ready and clean everything with alcohol and peroxide. Don't mix them but peroxide is whats going to kill mold spores and the alcohol is good for getting all the gunk off the fans and killing bacteria. i got bot rot on some really thick colas and it took me a good 3-4 hours to clean/disinfect my 4x8tent and all the accessories. fans were covered in trichomes and dust and whatever else spores and nastiness.