Hello dear, The swelling & black discolouration is due to accumulation of fluid and blood (hematoma). The blood cells which gets accumulated are eventually broken down and absorbed in the body. But this is a slow process & takes times to disappear completely. Till that time, symptomatic relief is obtained by taking analgesics, ice compression & adequate rest. However, if there is any hidden injury to the brain or minor intra-cranial bleeding, then it may take some time for the symptoms to develop. So it is important to maintain caution for 1 week. If the symptoms still persist or associated with any other complaints like dizziness, vomiting, loss of consciousness, convulsions, etc., then it will be better to consult your Physician. Investigations like X ray of the head & neck region and CT scan will be helpful to rule out any fracture to the facial & cranial bones or any trauma to the brain. There is no need to worry, you will be fine. Wishing you a good health. Thanks & take care.