Hello dear, The lump formation after injury 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 ice compression, adequate rest & analgesic preparation like Diclofenac+ Serratiopeptidase. If symptoms still persist, kindly consult an Orthopedician for proper clinical examination. X ray of the affected leg will be helpful to rule out any fracture or other pathological causes. Wishing you a Good Health. Take care.