You need to let your Instructor know of your injury due to his or hers liability insurance they should have. This will prevent you from having to pay for medical treatment. You need to see a Dr. due to the possiblity of greater injury than you may realize due to radianting pain with movement.
You need to take an anti-inflammatory medication like IBU 200 mg take two tabs every 4-6 hours unless allergic to it. Rest and elevate your leg and apply ice every 10 - 15 minutes every hour.