Hi,
Depending on what actual screen-protector you are using, you should be able to peel off the cover, and re-stick it down. The protector, should also have come with a small piece of card or plastic, which is your "sponge/squeegee", and a small piece of cloth, which is to be used to clean your iPhone's screen, before you place the protector over it.
However, with that all said and done, you may just chose to get another protector, and use this as a mildly-expensive lesson... just as many others have done before you, including myself.
Pooch