Hi , I noticed a bad smell in the back entry room, which is below the garage attic which has the vent pipe in the roof. The smell was in the air, not near any wall or floor or door. I suspected a leak in the vent pipe, and the plumber found a water mark in the ceiling of the back closet. He sealed the pipe underneath and above, and the smell seemed to go away a few days later. Do you think this was the cause of the smell, and if so , is there damage to the dry wall inside the walls and ceiling that will make the smell worse ? Or will it just dry up and not be noticeable?

I would adopt a "wait and see" attitude" for now. I would allow the drywall to dry and then is the smell's still absent you've removed the stinky. Good luck, Tom