Ebay payment issue, a little help?

Okay, I just paid for an item on ebay thru paypal, and I was planning on paying via two bank accounts, but according to the paypal website, I set my backup payment (to cover the remaining cost of the item) to the debit card to the same account by accident, rather than to my other bank account. Is Paypal going to charge my other account automatically or no, and if it doesn't, how do I do so without accruing any consequences? Such as interest, which I'm guessing could be REALLY high.