Hello, I have studied your case history. Traumatic hit injury can lead to bruise due to hematoma formation. You will need X ray of knee to look for bony anatomy. Clinical examination is important to rule out knee ligament injury For these symptoms analgesic like ibuprofen and chymotrypsin medication can be started. Apply crepe bandage over leg or use supportive splint. Do ice fomentation and rest to leg. Hope this answers your query. If you have additional questions or follow up queries then please do not hesitate in writing to us. I will be happy to answer your queries. Wishing you good health. Take care.