Yes. Even if you think you were not injured and feel OK after an accident, you should seek medical attention immediately. There are two major reasons for doing this. The first is that many injuries do not show themselves for days or even weeks afterward. Immediately after an accident, your endorphins and adrenaline are likely to kick in and cloud your pain response. Because of this, you may not feel a soft tissue injury like whiplash for days after the accident. A doctor would be able to assess the possible damage to your muscles and bones in advance of you feeling any pain. And in the case of internal injuries, you may feel fine but be bleeding internally. Undetected, this could cause major complications or even death in just hours.
The second reason to contact a physician immediately is to document the injuries you sustained in the accident. The insurance company will do anything that it can to pay you less than your claim is worth, and one way that they do this is by saying that your injuries were not a result of the accident. If you wait to see a medical doctor until weeks after the accident, you are giving the insurance company a basis to claim that you received your injuries sometime between the accident and your first doctor’s appointment. And the challenging part is, it would be tough for you to prove otherwise.