My HSA reimbursed me the excess contribution amount before April 15. How do I report this taxable amount while filing tax other than getting my W2 corrected?

When you were in the TurboTax HSA interview, and TurboTax told you that you had excess contirbutions, then if the excess contributions came from the code W amount in box 12 of your W-2, TurboTax immediately added your excess to Other Income on Line 8 on Schedule 1 (Form 1040), where it will be taxed.

If your excess was because of a direct contribution that you made (not through your employer), then the amount that would have been reported on line 12 of Schedule 1 is reduced by the amount of the excess.

In either case, you don't have to do anything and please don't go asking your employer for a corrected W-2.

TurboTax has already taken care of what needs to be done on the tax return side.

[Edited 3/20/2020 1:36pm CDT - updated for 2019]