What usually happens in this case is pretty common. You see, when the screw gets in the tire air sneaks in between the internal layers of the casing because the internal seals between layers gets broken. Air get in there, thus forming the bubble. That tire is now rendered unsafe, so I would not suggest driving on it any further. If you need help locating a replacement, let me know direct and I'd be happy to help. thanks Aaron 800.428.8355 x395