You can go back into your return and walk through the steps to Amend Your Return and enter your W2-C to see the affect on your return. When your employer did the corrected W2 it was sent to the IRS, so they now have the correct amount reported to them.
If too much was withheld, you should have had a warning in TurboTax before you filed your original return to not file, but to contact your employer for a corrected W-2
Social Security taxes are generally only reported with your return when you are self-employed as part of your self-employment taxes or when you tell TurboTax that your employer did not withhold enough social security taxes. TurboTax does not automatically calculate or report an underpayment of social security taxes based on your W2 entries. You would have to enter it on form 8919 which would then go to your schedule 2 which would then go on line 23 of your 1040.
Again, you can go back and take the steps to Amend Your Return , to be sure there is no change. If there is no change, you will just need to delete the 1040X and log out without e-filing your amended return. You may be able to still submit it via e-file, but you may get a warning that says there is no changes do you still want to amend.
"If you discover an error after filing your return, you may need to amend your return. The IRS may correct mathematical, clerical errors on a return and may accept returns without certain required forms or schedules. In these instances, there's no need to amend your return. However, do file an amended return if there's a change in your filing status, income, deductions, credits or tax liability. " Topic 308
