Maybe a half build now and a full build later?
We don’t know if the mother fully supports their child’s decision to become a dragon.

On the one hand, a partial regeneration would be safer, but it could lead to a poor negotiating stance due to mistrust. On the other hand, a full regeneration might show proper respect and improve the stance. So, I say a full regeneration with a stern warning of destruction if she refuses negotiations. Along the lines of: “Timberwolf spirit that dwells in this core, I am here to negotiate for the Timberdragon. You have seen me in combat, and know what I could do. I am willing to negotiate for your daughter’s freedom. You will be treated well as long as negotiations last, but I will defend myself and the Timberdragon. I am allowing you to regenerate fully as a token of good will. Don’t make me regret this.”