Car in accident, hit in passenger rear side and right front, after fix the gas gauge doesn, t work right

Yes, it does sound damaged. There is more than likely a bend in the float arm, whether it is a lever arm or a post style float, that the float is hangin up on. Hover, check the connection first anke sure it is good as improper voltage signals can cause a gauge to be jumpy. Also there is what I think is called a histometer, which is a sensor in the tank that sets off the near empty light on dash, check the connection on it as well.