Now that is a serious question (and I hope that's not you). What will happen is if you don't buy to cover, the broker you have will and at market... yes that sucks. If I were short I would cover while I had enough money in my account to cover, or else they will hold you responsible for the defaecate.
One of two things. If you do not have "Margin" with the broker I believe they call it due immediately. If you have margin you will be able to borrow against any assets in your account that has enough value to give you borrowing power. once it goes past this amount you will have 5 days max to clear things up. Unless the price rises so much it becomes an issue with the broker and they want to just cash you out to protect themselves against losses and you as well. So is not a one day event. It can go on for weeks if there is a huge short and the price continues to rise.
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