Hiya,
As noted, the Butterspider Box has a regeneration option. That will be making an appearance for ED Revised in the Parlainth sourcebook, but you can extrapolate from the original ED1 box set easily enough.
In my campaign, I've had one of players (a windling Thief) have his wings burned off several times now (long stories involved in both cases). To me as a GM, it's more about using the opportunity to build a better story, than relying on game mechanics, in such "extreme" situations. So the character is in a good deal of debt to both a great dragon AND a major shrine to Garlen (and the Passion, of course). I will mention that the great dragon is beginning to regret the deal ... but that's an even longer story.

Bottom line: if the player is really attached to their character, then use it to your campaign's advantage.
Hope this helps!
Take kaer, James