Yes, you may return to the Business Income section (Schedule C) to revise the information for your business.
The easiest way to find Schedule C in TurboTax is to use the Search box at the top right side of the TurboTax header. Enter "schedule c", hit Enter, then click on "jump to schedule c". This will take you directly to the start of this section where you can set up your business and enter your income & expenses.
Or go to My Account >> Tools >> Topic Search. Type in "schedule c", click the topic in the list, then click "GO".
(If you are using the mobile app and don't have My Account or Tools on your screen, try logging into TurboTax from a laptop or desktop browser.)
Click Edit beside the business you need to review. Continue to the Business summary page and click "Update" beside Business Income. Click Update beside General Income.
Your entries from Form 1099-K should be already entered. You may revise this number to include all income you earned from your business (including 1099-K). Continue to the end of this section to save your changes.