Let it do it's thing. If you are lucky, it's a wild yeast fermentation and you'll get a nice sour out of it. More than likely it will be a vinegary mess - but at this point what's done is done.
Kegged: Waldo Lake Amber, Notty as Helles, Vanilla Porter, Sweet Stout (nitro), NB Surly Furious Clone, Petite Saison D'ete, Le Seigle Belge Saison, BM Cream of 3 Crops, Edworts Apfelwein
In Process: Braggot
Upcoming Brews: Surley Furious Clone, Uintah Wyld