I Received A Kenalog Injection In Between Cervical Vertebrae At

I received a Kenalog injection in between cervical vertebrae at about 2 pm 11/17 A t 11:30 PM, about 2.5 hrs after dinner my blood sugar measured 290. I took a 500 mg Metformin and measured again 10 minutes later and it registered 278. I do not feel nauseous, just a bit light headed. How or should I even be concerned about this? My glucose level rarely exceeds 150 mg/ml.