If her tooth is shaking and she is in pain, in all probability that tooth had been traumatised at the time of the fall but is showing its effect only now. Most likely that there is infection at the base of the tooth and that it causing the pain. Whether to remove the tooth or save it will be decided by the specialist after checking the clinical condition of the tooth and maybe also taking an xray. A children's tooth specialist is specially trained in handling kids teeth and would be able to give you the correct guidance. Her haemoglobin levels and other medica factors will be taken into account to ensure that whatever treatment is done is for her benefit and without any risk.