Take a small belt sander, or grinder and carefully taper around the end and remove most of the damaged threads. Use some oil and start the nut back on the good threads.
If it works you can work on getting the hub off of the splined shaft.
Brush off any corrosion on the splines, Heat it up with a torch, then quickly cool it with water or some penetrating oil. tap the hub with a hammer and pull, Repeat as necessary.
If it does not work maybe you can borrow a large set of hub pullers.
Worst case you have to buy a new CV axle to go with your new wheel bearing. Next time use a large brass punch or a block of hardwood instead of hitting the threaded end dead on.
