Hello dear,
The bump formation in head after fall is due to accumulation of fluid & blood and it is called
Hematoma.
The blood cells 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 analgesics like Diclofenac+
Serratiopeptidase preparations, ice compression & adequate rest.
If it still persists or there are any other associated symptoms like fever,
severe headache, blurring of vision,
vomiting,
loss of consciousness, convulsions, etc...then it will be better to consult your Physician.
Under such circumstances, a proper clinical+ radiological evaluation will be needed to rule out any pathological cause for symptoms.
Till then, maintain adequate hydration & nutrition status and avoid stress.
Wishing you a good health.
Take care.