That I do not know as of yet. If it means anything, Wex says he was with a woman, with his wolf. They've gone to Skagos.

(( Though he wished they gone over the Wall, if the stories of the Skagosi are true. ))

You have seized Winterfell, but when I bring the Stark boy and his wolf to Manderly and the rest lords, it will be proof that you didn't kill them as believed by the Seven Kingdoms, and once again there will be a Stark in the north. It will prove the Boltons as the liars they are.