If you entered the Form 1099-R that reported your 'deemed' distribution from your 401k (since you did not pay the amount back before leaving the company), then the distribution amount will be included as taxable income on your return and you may owe an early distribution penalty.
All of this will be incorporated as part of your tax return, not as a separate payment that you owe. If you are still getting a refund on your return, then that is good. It means the impact from the distribution may not have been as bad as you might have expected.
Take a look at Line 4d of Form 1040 to see how much of the 401k distribution was taxed. Form 1040 Schedule 2 Line 6 will show any early distribution penalty you are paying.
@Pherson
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