Yeah, that looks a bit nasty... wish you had a diary here, mate, it would help at least a little. My one thought is that this might be bud rot - especially as you say it's pulling away... if you grab some of the bud, does it come out easily? If so, that is definitely boytritis (bud rot).... it's a fungus caused by humidity being too high - which is where the diary would help to confirm the suspicion (or tell me I've got rocks in my head). Your best shot is to do some research and determine if that is indeed what is going on. If it IS, do NOT smoke anything that has the rot on it - it will do major damage to your lungs.
Here are some articles to get you going...
https://www.dinafem.org/en/blog/botrytis-mould-grey-prevent-identify-eradicate-plants-marijuana-cannabis/
https://www.amsterdamgenetics.com/bud-rot-botrytis-on-cannabis-prevention-and-treatment/
https://www.alchimiaweb.com/blogen/botrytis-gray/
Good luck... I hope I'm wrong!