There is no one definitive answer to this question. Some bike helmets can be replaced after a fall, while others cannot. It depends on the specific helmet and how it was damaged.Generally, if a bike helmet experiences a significant impact, even if the damage does not seem major, it should be replaced. This is because bike helmets are designed to protect against one major impact only. So if your child falls off their bike and hits their head, and their helmet takes the brunt of the impact, then it's likely that the helmet has been damaged and should be replaced.However, there are some cases where a child's bike helmet may not need to be replaced after a fall. If the fall was relatively minor and did not cause any visible damage to the helmet, then it is probably safe to continue using it. But it is still important to keep an eye on the helmet for any signs of damage, and replace it if necessary.Overall, it is generally a good idea to replace a child's bike helmet after any significant fall. This will help ensure that they are kept safe in case of another accident.