That’s one way to look at it. But a lawyer doesn’t necessarily try to “prove” that a certain injury resulted from a car accident as much as they take all necessary steps to put you in the best possible position to get a satisfactory outcome for your injury claim.
In this way, it’s more your doctor who will “prove” that any nerve damage you’ve suffered can be tied to your car accident. When you describe to your doctor how the accident happened, which parts of your body are injured, and the symptoms you’re experiencing, he or she will be able to make an educated diagnosis of those injuries and whether they are typically associated with a car accident.
Another factor that may come into play here is whether or not you have any kind of pre-existing condition that could be to blame for your nerve damage. You don’t need to produce every medical treatment record or bill you’ve ever received to show that you’ve never experienced nerve damage in the past, but be prepared to refute any such accusation from the insurance company. Insurers like nothing better than to point to an alleged pre-existing condition as justification for making a low-ball settlement offer or denying a car accident injury claim altogether.