Stay safe, call 911 for a police report, and get a medical check right away....

https://travistrcm708.theburnward.com/what-if-your-injuries-get-worse-days-after-a-car-accident

Stay safe, call 911 for a police report, and get a medical check right away. Snap photos and gather witness info, but don’t discuss fault. Avoid giving recorded insurance statements and keep track of your filing deadlines. Texas law moves quickly.