Hello and thank you for your question!
Traumas are the most common cause of knee problems like you have. The knee is a larg joint and it consists of some structures including the
meniscus, ligaments, tendines, muscles and the bone of
patella. So the injury you had might have damaged one of this structuris.
Its reccomended to do some exams to be able to have a right diagnosis.
First of all i would reccomend to do a X - Ray and see if there is a damage (
fracture) of the bone or damaged carilagines.
Second i would reccomend to do an
Ultrasound of the other structures including ligament and muscles to see if there is any damage of them (rupture).
If the knee is swollen it is reccomended to put some ice packs on it to reduce the inflamations. For the pain managment its reccomended to take some NSAID (if you dont have any Contraindications taking them) if so, you should take
Acetaminophen.
Best regards!