Usually pets recover fully from ingesting weed. But you CANNOT leave them alone while they are still affected, for the same reason you would not leave a human who ODd alone. They may slip into a coma or choke on vomit, so don't leave the room. Keep your dog warm and hydrated and be ready to take it to the vet immediately if it stops responding to stimuli. Personally, I'd like to see the dog vomit before deciding not to take it to the vet, because getting undigested/unprocessed weed out of its stomach is going to make the ordeal a LOT shorter.

Michigan Veterinary Specialists - Marijuana Toxicity

^^Here's some info and you should look for more, or call the vet and ask what to do. ^^
With the exception of Weedy, we are NOT trained veterinary professionals here, and you wouldn't ask the guy at 7-11 how to change your oil, you'd ask the mechanic next door... it's awesome that you respect our advice here, but not all of it is safe, so I think it's best this thread end. Good lcuk.