Because your tax return was accepted by the IRS you will have to file an amended tax return using Form 1040X to include the SSA-1099. You may also need to amend your state return if your state taxes SSA income.
This link How to amend (change or correct) a return you already filed provides information on how to amend your tax return.
[Edited 03/10/2020 | 9:41 am PDT]
