Can anyone tell me why I don't have custom hair showing in CAS? (Never used it there before so don't know if it was working there or not).

Dunno if I've got it in game yet. The last time I used it was a couple of months ago.

Ok, first of all which hair is it? and where did you get it from?
Second is it a recolour? or a new hair? If its a recolour do you have the EP/SP the original came with?
If its a new hair, do you have the mesh?!
And last of all, how is it not showing? is it all blue? is the sim bald? is it just nowhere to be found?

The answers to those will tell how to fix it

N0 none of those...

You know when you're changing an appearance (or in CAS) how you get the hair screen, and you have the four colours and then the starish type thing - I meant the starish type thing when I said custom hair. (Sorry for the confusion)

I meant the weirdo hairstyles with purple green, blue etc .

That section is not available in CAS - has it always been like that or is that new?

oooohhhhh I understand now
Those custom hairs aren't available as genetic hairs, so they aren't available in CAS. When you choose a hair in CAS that hair becomes the genetic hair for the sim, and if you dont have CC hair that is not colour binned, the asterix for CC hair wont show.
To use it, you have to make your sim, then take them to a mirror and change the hairstyle, but the genetic hair wil always be the one you first chose for them.

Oh my golly.

All these years playing Sims and that's the first time I've tried to make a sim with weirdo hair??? LMAO!!!

Cool, thanks for that. At least my game isn't broke!