It actually might not be too much effort to fix it.

A friend of mine recently changed the dihedral of one of his wings. He hacksawed down the centerline. Turns out that the inside ribs were plywood and the hacksaw blade left most of the ply on each side. He then sanded the new angle in, half to a side, and re-epoxied the two halves.

In your case, after you saw the two halves apart, you'll need to remove the excess epoxy. You'll need to get that out of the way so the two halves will mate at the correct angle. Good thing is that the longer cure epoxies will bond to cured epoxy strongly. So any residual cured epoxy won't weaken the joint. Resist the temptation to reglue with 5 minute. It doesn't stick to cured glues as well as slow cure does.