One of the most dangerous things that come about from improper form is a strength imbalance. When you use poor form, muscles that are not designed to engage are fired to hold up the weight. Usually these muscles twitch and waver as your body tries to hold the weight up off the ground. You are essentially just trying to balance. When muscles are fired in this fashion, you start to develop muscles in an irregular pattern.
When your muscles become imbalanced, you start to tug on your skeleton in strange ways. This can actually move your spine out of place. This can lead to herniated or slipped discs. But most importantly, it can lead to a subluxation.
A subluxation is an imbalance in the spine that puts stress on your cardiovascular and nervous systems. An imbalance of this sort can make it difficult for blood to get to certain extremities and it can pinch nerves running through the spine. This can lead to sciatica and increases your chances of injury.
All of this needs to be worked out with some athlete-only physical therapy and proper physical training. Training with good form is the only way to reset your body and exoskeleton properly.