When I had steroid injections (for arthritis) in my basal thumb joint, it was about three or four days before things started to normalise again. My sugar levels were more unpredictable for a few days after that, but were clearly headed in the right direction. I didn't put up my basal insulin, because experience had made me mortally afraid of overnight hypos and I knew my waking level would best indicate when the effect of steroids was wearing off. I never found any nurse or doctor prepared to offer any real advice as to the best course of action in this situation. They said it depended on the individual.