Thanks for posting your query.
You should immediately consult with orthopedic surgeon and should go for x ray
of the affected knee on urgent basis.
You may have hair line fracture
of patellar bone or may have soft tissue injury
Patella fracture needs urgent treatment as this form part of knee joint and may restrict your knee movement in future.
You should also take pain killers for immediate relief.
Dr. Mayank Bhargava