I'm having trouble finding an answer to this because I keep finding
topics on "fix cracked drywall with joint compound", but I want to fix
cracked joint compound. Thanks for any help.

I took out my bath tub and replaced with a tile shower about 6 months
ago. I put up hardibacker and it didn't quite line-up with the rest
of the existing drywall. It wasn't too bad, I thought, only off by
about 1/8". I applied tape and drywall compound to make up the
difference. Pretty much as soon as it dried, it was cracked all
over. The cracks look like a spider web pattern (pretty much
random). I secured the heck out of the hardibacker so I don't think I
have movement, I think maybe I just applied the drywall compound too
thick, or otherwise incorrectly. It was pre-mixed, so it wasn't that
I mixed it incorrectly.

Anyway, I'm wondering if I can apply another thin layer over the top,
or if it will just continue to crack? Do I need to apply a mesh, or
something? Or do I need to rip out the drywall and start over. No
way I'm ripping out the hardibacker, since that would mean redoing the
tile... I'd do wood paneling, or tile the whole bathroom before I do
that.

O-ya, and if anyone can point me to a web-site (with pictures would be
great) with info on this topic, that would be awsome!