@pfehlman1 per SSA records, if your full name and SSN does not match, the return would be rejected. Then do the needful.
If the return is accepted for processing then you have to get the SSA records corrected before doing anything ( IRS uses SSA data base -- copy thereof and sometimes is not upto date )
The tag below your question indicates that you are using TurboTax Live. You should contact a TurboTax Live tax expert to discuss the situation and find out what, if anything, you have to do. You are paying extra for that service.
Have you already filed your tax return? If not, just go back to My Info and correct your last name.
If you have filed your tax return, did you e-file or file by mail? If you e-filed, and it was accepted, you do not have to do anything. If you filed by mail, wait to see if you get an IRS notice about your name, or if they process your tax return as-is.
The IRS checks the last name on your tax return against your last name in the Social Security records. If you changed your last name, but did not change it with Social Security, then it was correct to use your old name on your tax return.
The IRS only checks the first four letters of the last name. If the first four letters of the correct name and the name on your tax return are the same, it will not be treated as an error.