Nothing can be done, I'm afraid. Yeast create gasses that get trapped as tiny bubbles in the dough. Those bubbles become the air pockets you see in the bread's crumb. The dough in the interior of your undone bread has collapsed on all these little air pockets. Yeast die in oven temperatures, so no new pockets are ever going to form in the collapsed portion of the dough. Putting it in the oven (or cooking it in any other way) is simply going to harden that undone dough into something heavy, solid, and very un-breadlike; it's not going to re-inflate.
So, what can you do? 1) You can cut away the uncooked portion and use the remaining bread for croutons, stuffing, bread pudding, etc. 2) Sometimes, accidents like this lead to creative solutions. You might consider slicing the loaf in half horizontally, scooping out the undone portions, and filling the cavity with some kind of a sweet filling that would compliment the bread - like perhaps a cream cheese and nut mixture. Put the two halves back together, and slice into portions.