After you file

Agreed ... look at the 1040X ... was the refund you got the same as the amount on line 18?  If it is there is nothing you need to do. 

 

Column A should have the figures from the original return, Column C the corrected figures and Column B the differences between the other 2 which needs an explanation on page 2 of the form 1040X.

 

If you completed it correctly you will see an entry on either line 16 OR 18:

On line 16 should be the amount you paid with your original return. 

On line 18 should be the amount of your original refund you received.

 

Then you will see your extra refund on line 22 OR  the new balance due you need to pay on line 20.