I have already filed my 2023 taxes BUT i forgot to enter my mortgage info (1098). Is there anything I can do to fix my error after the fact?

If accepted you can only amend it. But wait until the first return has been processed and any refund or tax liability settled. 

If you are taking the standard deduction and adding form 1098 Mortgage Interest would not put you over the standard deduction, then form 1098 won't impact your return and you don't need to amend.