Just to clarify - if you claimed dependent care (you would see a form 2441 in your pdf of your tax return) but did not have dependent care then you will need to amend to correct the return.
TurboTax does support that and even supports efiling the return. It looks like some already posted the how to link but here it is again:
https://turbotax.intuit.com/tax-tips/amend-return/how-to-correct-federal-tax-returns/L67t0F7il
You want to amend the return as soon as possible to minimize any interest the IRS may charge you for late payment of taxes.
Also, be sure to check your state return to see if it also needs to be amended.
