Do cortisone shots ever permanently take knee pain away? Is ir possible?

Unlikely. Depends. Most shots are for arthtitic conditions (degeneration, inflammation) and in these instances they provide temporary relief. In bursitis, often just below the knee, it can be a permanent fix.
It may could. If the knee for example if you inflammation no permanent changes. Or if you have traumatic injury but no permanent damage. Good luck. Thank you.