After completing the traversal, the last node ends up at the second node in the reversed doubly linked list. To obtain the new head of the reversed list, we simply use the backward pointer of the last node, which points to the new head.

To ensure that we handle the case where the traversal ended at the original list's end (i.e., the last pointer is not null), we update the head pointer to point to the new head of the reversed list, which is stored in the last pointer.

Finally, we return the head pointer, now pointing to the head of the fully reversed doubly linked list.