It's not legally necessary to have proof of medical treatment in order to make an injury claim with your own car insurance company or with the other driver's carrier after a car accident. You can make a few phone calls and fire off a demand letter and hope for the best. The carrier may even cut you a check for a small amount just to make your claim go away. The insurance industry even has a name for this: it's called a "nuisance value" claim.
But if you want the insurance company to take your claim seriously, it's crucial to provide proof that your car accident injuries required medical attention. So, if you're feeling any kind of pain, stiffness, discomfort, or just a feeling that something isn't right with some part of your body, don't wait to get medical treatment after a car accident.
Once you explain to your doctor how the accident happened, and what kind of symptoms you're feeling, he or she will conduct a thorough examination, run proper tests, make a diagnosis, and recommend a course of treatment. That treatment can range from rest and over-the-counter pain medication to physical therapy, and even surgery in some cases.
Even if you're experiencing whiplash-type pain or some similar kind of soft tissue injury that may not show up on an x-ray or an MRI, going to a doctor and getting your injuries "on the record" is important when it comes time to put a dollar value on your claim. Your medical bills, the seriousness of your injuries, the extent of your medical treatment, and the impact that your injuries have on your life all factor in when you (and the insurance company) are figuring out what your car accident claim is worth.