Honestly, I would just ask the doctor to prescribe the Olux steroid creme foam for you to apply as needed on your scalp instead. Long time ago I had a dermatologist suggest I have these steroid injections for my elbow and sometimes scalp done. It does work, but over time, as other folks here confirm, it doesn't really work anymore. That's the case with any treatment really, as there is no permanent cure.
All the steroid shots did was help the dermatologist rake in more money, as it required that I went back for shots every 2 weeks, and I eventually felt sharp pains in the area of the shots, so I stopped. My scalp psoriasis is under control with occasional Olux use. I refuse to get shots again. Good luck.