Gas can broke off into car. What do I do?

I drive a 2001 ford excursion with a 44 gallon gas tank and today when I was refueling my car the top part of the nozzle slid off when I pulled the can out and it fell into my fuel reservoir. How concerned should I be? Is their anything you can do about this or do I have to buy a new fuel tank and install it?

Since the filler tube is going to be double walled, the gas can part will likely be trapped within. It is double walled to let the air leave when the fuel enters. There's at least 2 areas where it bends, then a length of hose entering the tank from the internal tube.
Have the service dept. Remove the tube and extract the part, or if it won't come out, you may experience choking. At times when it obstructs, the fuel may be slow to go or the air to leave.
Replacing the filler tube could be the answer as applicable.

You don't have to do anything. The plastic or metal nozzle will just lay in the bottom of your tank. Or it is stuck in the filler tube.