Preheat oven to 350°F. Grease a 9×13-inch baking dish

In a medium-sized bowl, combine the cake mix, eggs, vegetable oil, and water. With a hand-held mixer blend until smooth. 

Transfer the batter to the prepared baking dish and bake for 25-30 minutes (or until the cake springs back when lightly touched).

Remove the cake from the oven and allow it to cool for 30 minutes.

Using the end of a large wooden spoon, poke the cake with a series of holes, (the more holes the better, to allow the ingredients to soak through).

Slowly pour the sweetened condensed milk over the cake (concentrating on filling the holes). Refrigerate for 15 minutes to allow the cake to set. 

Remove the cake from the refrigerator and pour 1 cup of the caramel sauce over the sweetened condensed milk layer. Place the cake in the refrigerator while you make the whipped cream layer.

In the bowl of a stand mixer fitted with the whisk attachment, mix the softened cream cheese with ¼ cup of the heavy cream on medium speed until smooth. Slowly add the remaining heavy cream and powdered sugar and beat for 2 minutes. Increase the speed to high and continue beating until soft peaks form (about 2 more minutes).

Transfer the whipped cream to the baking dish and spread it over the caramel layer.

Drizzle the remaining caramel sauce over the whipped cream and sprinkle with broken pieces of Heath candy bar. 

Chill for 15 minutes before cutting and serving.