If you were fine after an accident and only realize that you have been hurt later, you can still be compensated. But there are time limits. For workers compensation claims it is 3 months and for car accidents 2 years. But you need to have reported the car accident to your insurance company within 7 days and notified the defendant within 120 days of the accident that you are seeking compensation. If you don´t you may not be able to claim. It is easy to make a mistake and end up trying to claim too late. So, speak to a personal injury lawyer.