I'm sorry to hear about your fall and the knee injury. Abrasions and swelling after a fall are common and indicate some soft tissue injury.

Here are some steps you can take to care for your knee:

• Clean the abrasions gently with mild soap and water to reduce the risk of infection.
• Apply a topical antibiotic ointment such as Fucidin Ointment to the abrasions to help prevent infection. This ointment is prescription-based, so please consult a doctor to obtain it.
• Use a cold compress or ice pack wrapped in a cloth on the swollen area for 15-20 minutes every 2-3 hours during the first 48 hours to reduce swelling.
• Keep the knee elevated as much as possible to help decrease swelling.
• Avoid putting too much weight or strain on the injured knee until it feels better.

If you notice increasing pain, redness, warmth, pus, difficulty moving the knee, or if the swelling worsens, please seek prompt evaluation by an orthopedic specialist. They can assess for any deeper injury such as ligament damage or fracture.

For now, gentle care and monitoring are important. Please consult an orthopedic doctor to get a thorough examination and appropriate treatment. If you experience severe pain or inability to walk, consider visiting an emergency facility immediately.To narrow down potential causes, we will need some more information.I understand you fell and hurt your knee. To help me understand your situation better, could you please tell me your age and gender?