Immediately call your nearest vet even if it is ER. Ask them if you should induce vomiting prior to bringing him in. If they say yes give him 1 tablespoon of Hydrogen Peroxide to bring it up and take him into your vet asap.
If he is unable to vomit it back up do not wait or give him more just take him to the nearest vets office. Some of these oils can be highly toxic to your dog.