Numbness in your left hand and joint pain after a car accident may suggest nerve compression, nerve root irritation, joint injury, or a fracture, so it should be promptly evaluated by a doctor. You should avoid taking medicines or injections on your own and instead undergo a proper clinical examination with imaging if required. You may use over-the-counter pain relievers such as paracetamol, diclofenac, or ibuprofen to help with joint pain, provided you have no stomach, kidney, or bleeding problems. Avoid heavy lifting or sudden neck movements and keep the arm in a neutral position until you are examined.