"which I accidentally added to tax year 2021." - So did you make the contribution after January 1, 2022, but actually told the HSA custodian that it was tax year 2021? That's not usually an accident (usually, the accident is making the contribution in 2022 and NOT saying it was for 2021).
"I filed my taxes not knowing this so the contribution does not show up anywhere as reduced taxable income." What were you not knowing? Which year the contribution counted for or that which year it was supposed to show up as reduced taxable income?
Did you have excess HSA contributions for 2021? If not, why don't you just take the deduction in 2021?
I don't understand your situation, because most taxpayers would prefer to do what you accidentally did. Please give me more detail.
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