There are several things you should try and avoid saying after a crash, including “I’m fine” or “I was not paying attention.”
When you say things like this you are either admitting you do not require medical assistance or that you were at least partially at fault for the crash. It is crucial that you do not admit any fault for an accident and that you always get medical attention even if feel OK. You never know whether serious injuries are just taking time to appear.
You should also avoid posting about the crash to social media, as the insurance company is likely going to try and use anything you post against you.