No, don't get caught by the slugs.
The slug nest is in the jungle. You visited it before as part of a quest. From the jungle campsite, go to the right and climb up the vines to the new area. Then go all the way to the north-west (top-left) of this area and jump up a ledge.
Then proceed down a hole and you'll be in the slug nest. Make your way to the far side of the slug nest and you'll find a way out. The merchant is on the other side.