I Received A Cortisone Injection ( 1/2 Cc) On Sat.

I received a cortisone injection ( 1/2 cc) on Sat. evening at a walk in clinic. Along with a Rx for Cefdnir 300 mg.
I had no reaction until this morn. I woke up with red flushed swollen cheeks and chest discomfort.
I am currently taking coreg 3.25 and Brintellix 5 mg.
I am reluctant to take the next dose of Cefdnir or could this be a delayed effect of the injection.
I do have a call into the Dr., but still waiting.
Thank you