It is good that the dog has been bathed with the dawn. No way to tell how much was absorbed. You need to watch for any side effects like vomiting, lethargy, neurological problems, etc. If you see any of these signs, I suggest you get to an ER. You may want to but I see you posted this some hours ago. Do call your Vet first thing in the morning for advice as to what to do.
Good luck and please come back to update.