A child’s forehead knocked a big bag is mainly due to trauma caused by local hematoma, can be treated by first cold compresses and then hot compresses, medication and so on. 1. Cold compresses first: within 72 hours after a child’s forehead knocked a big bag, you can first put a towel in the refrigerator to cool down, or use a towel wrapped in ice to the injured part of the cold compress. 2. Hot compress: After 72 hours of injury, use a hot towel or a cooked egg to apply a hot compress to the injured area to promote local blood circulation and speed up the swelling. 3. Medication: If the swelling does not subside after applying cold compresses and hot compresses, it is generally because the subcutaneous hematoma has not fully recovered, and at this time, you can also use medications such as Mucopolysaccharides Polysulfonate Cream to promote swelling. Once found a small child forehead knock a big bag need timely medical treatment, improve the relevant examination, to avoid sequelae. Another tip, if you need to use drugs should be used under the guidance of a doctor, to avoid allergies and other side effects brought about by drugs, do not blindly use drugs.