Is there anything i can do? ?

If the other driver was at fault and you have their insurance policy and contact information, call the company and tell them that you have latent pain that you need to get checked out and ask how they would like to pay for it. Be sure you have the accident particulars including the police incident/accident report number and names of the parties involved. If they decline, you can go for medical treatment and then sue them for reimbursement (IF the other driver was found to be at fault). In the meantime, you can try ice for the pain in the knee and lumbar spine and over-the-counter anti-inflammatories.