Is Specialist Advice Required For Taking Cortisone Injections For Prurigo On Scalp?

I have been diagnosed with prurigo nodula on my scalp. I recieved injections of cortisone which cleared up a lot of the nodules, can my regular gp administer the injections or do I have to keep going back to the specialist? The specialist is very expensive.Dr. Andrew Rynne is very close to where I live