Hair loss & cortisone injections

You need an exam and a DIAGNOSIS of what you have / why you are losing hair.  If you know the cause, you can consider a treatment.  TRYING steroid injections for what? You need to have more understanding and clarification from your doctor.  

In general, cortisone injections are used to halt inflammation and used in conditions such asalopecia areatatraction alopeciascarring alopeciaotherThe most common agent is triamcinolone acetonide and concentrations 1-10 mg per mL are used. While any concentration still has the potential to cause "indents" (atrophy) it is quite rare for concentrations less than 3 mg/mL. The medicine is diluted in saline (salt water) or anesthetic, not water. In general, injections can cause telogen effluvium in some individuals (temporary shedding). Most,  but not all, fully regain hair after episodes of telogen effluvium. Steroids do not kill hair follicles. You may find this blog of mine from a few years ago helpful. 

first the cause of your hair loss should be established.  If it is typical genetic male or female pattern hair loss, then the cortisone shots are a waste of your money.