1. Hit it with a blow dryer or heat gun, get it up to where the epoxy softens (should be well below 150 degress F) pop the joint apart and reglue it.
or
2. Sand it, fill in the gap with epoxy/woodflour putty and paint over where you went through the veneer.
Obviously you don't want to do #2 with a varnished finish.
Good luck,
Laszlo