Thanks for posting your query.
You should go for x ray
of knee for clarification as you may have hair line fracture
and femur/ tibia
Are you able to bend your knee or there is some sort of restriction of knee movement?
There may be possibilities of ligament torn.
You should consult with orthopedics surgeon.
You should also take pain killers and muscle relaxants for better relief.
Get well soon,
Dr. Mayank Bhargava