Is it obligatory for me to do anything after I accidentally hit a person riding a motorcycle and fled out of fear of a crowd gathering, and I do not know what happened to him?

The driver's duty in vehicle accidents is determined by the circumstances of the accident. The driver is responsible for any bodily or financial harm inflicted upon others if the elements of error and damage are present. The driver is exempt from responsibility in cases of force majeure, or if the accident was caused by the act of the injured party, or the error of a third party. If the driver took safety precautions and did not commit negligence, then neither expiation (kaffarah) nor blood money (diyah) is required of him. However, if there was negligence, such as neglecting to inspect the vehicle or violating traffic rules, then expiation and blood money are required. The driver must review the reports of the competent authorities to ascertain his duty and clear his conscience.