HEAT oven to 350°F.
PRESS cookie dough onto bottom of 13x9-inch pan. Bake 15 to 18 min. or until lightly browned.
MICROWAVE caramels and water in microwaveable bowl on HIGH 2 to 3 min. or until caramels are completely melted, stirring after each minute; pour over crust. Top with remaining ingredients.
BAKE 5 to 7 min. or until marshmallows are lightly browned. Cool completely before cutting into bars.