I'm not sure on this since I never took a Cummins apart, but from my experience with other engines I think the head gasket is lower down below the intake/exhaust ports, no????
From the picture, it seems anti-freeze is coming from the bolt. Those passages under the head bolts are usally open to coolant and require sealant. If the sealant goes it will blow coolant past the threads and out below the head of the bolt.
Usually with blown head gaskets you'll get coolant mixed in the crankcase or steam out the tailpipe. And with a turbo, that steam/coolant may damage your turbo. I wouldn't drive it anymore.
Good luck and let us know what the dealer says!!!!