Man that's a bummer, been there and done that. I too tried to "fix" them but the reality is, take it apart and resand and refinish is all I ever came up with. If it's a slimline you may have to lose the transmission but you can buy a small bag of those for maybe $5 at WoodTurningz. If it's any other kit you can disassemble and save all of the parts. If the blank is really special it is worth the time and effort. The only positive I have found in doing this is, I learn how to take 'em apart and salvage them. I frequently will disassemble a pen that hasn't sold for a couple of years, turn the blank material off the tubes and make a different pen from the pieces/parts of the old one. Hope you can salvage the one you are dealing with.
WB