Hi... I need to know more about your case. I'll be able to guide you better after that. 1. Did your knee get swollen immediately after the fall (became almost double within half an hour)? 2. Could you walk immediately after the fall (could you give weight on your leg)?
If there was no swelling immediately steel the fall & you could walk too, then nothing to be worried about.
Next Steps
Apply ice to your knee for at least 2 hours AT NIGHT only.
Health Tips
Avoid painful movements. Have a happy healing... :)