Hello and welcome to e health forum.
Steroid injections can result in hyperglycemia and long term use of steroids for treatment of chronic conditions can predispose to diabetes mellitus.
In your case, if the effect of the steroids have weared off and the blood sugars have normalized , your current status can be determined by undergoing tests including fasting blood sugars, glucose tolerance tests and HBA1C.
If serial testing with the above modalities - provide normal results, then it is probable that you do not have diabetes and the hyperglycemia, could be due to steroid induced glucose intolerance, which in most probability would be short lived, once the steroid treatment is stopped.
You might consult with your treating doctor or a endocrinologist for any further advice and proper testing.
I hope this helps.