Accidentally bought stock without cash to cover

Selling the stock today might make the problem worse. It might result in a good faith violation, freeriding violation or cash liquidation violation, which might result in a temporary restriction being placed on your account.

Call your brokerage on the phone and ask them what to do.

If you already sold the stock, and your account now has a credit balance (that is, a positive balance) in cash, I can't think of anything further that you can do to make the situation better.

In Australia at least you buy & sell all through the day and owe (or are owed) your end-of-day net after T+2 days. So "yes" if your broker has allowed you credit to buy without a balance in your trading cash account. Any obligation is between you and your broker and whatever terms they gave you.

After 14 hours, I am guessing this answer is now irrelevant though.