How do I go about finishing up my state taxes after ive already filed my federal

You can absolutely finish filing a state return after you've already filed your federal. If you're using TurboTax Online, please see below for instructions. 

Instructions:

1. Login to your TurboTax account.
2. In the Welcome Home box, click Visit My Tax Timeline at the bottom.
3. In the SOME THINGS YOU CAN DO section, click Add a state.
   
4. Click on the State Taxes tab.
5. Click Continue to start or complete your state taxes.
6. Click Done with State.
7. Continue through the flow to review and file your state taxes.

Please see the following FAQ for more information and instructions if using TurboTax CD/Download. https://ttlc.intuit.com/replies/5269973