You won't be able to go back into TurboTax and set up a payment, but all state websites have a mechanism to pay taxes online or a form you can download to send in a check payment (you can also get this form online or if you download the pdf of your return in TurboTax you should see it.
Below is a list of state tax websites -
https://ttlc.intuit.com/replies/3302452
