This answer is for the first iteration of the question. It's not suitable due to subsequent edits.
This answer is for the first iteration of the question. It's not suitable due to subsequent edits.
I'd probably just say: I'd rather not.
If they keep pressing you, you could then say: I don't think we need to get into it
If you were feeling charitable, you could say: I've just gotten out of bed which may be slightly less embarrassing for you. Maybe they could join the dots.
And don't worry, I've done those types of meetings before, wearing my pyjamas. It's not just females with bed-head that don't want to be seen in the early hours.
If it is just the hair however, you could consider some sort of head covering. Or even a beanie. But that's up to you.