After hitting the head, for the scalp depends on the exact form of change. If it is just a simple contusion with no obvious bleeding tendency and no subcutaneous hematoma, the time to reduce the swelling will be about 6 days – 8 days. If possible, relief can also be provided by medication, such as swelling and pain capsules and appropriate cold compresses to reduce edema, which can also accelerate the swelling. However, if the brain tissue inside the skull is also swollen after hitting the head, the time to reduce the swelling depends on the change of the condition inside the skull, and it usually takes 2 weeks for the swelling to go down. And the swelling must be relieved and treated with appropriate medication, such as intravenous mannitol and prevention of cerebral vascular spasm, improvement of cerebral circulation, brain protection and other corresponding treatment before the swelling can be reduced. Therefore, the time to reduce the swelling of the scalp and the time to reduce the swelling of the brain tissue inside the skull are different.