What Causes Finger Stiffness And Triggering Despite A Cortisone Injection?

Hello. I had a cortisone shot for tendonitis (TF) in my middle finger about 8 hours ago. Directly afterwards, my finger was numb but I could move it easily. Now it has feeling, but is very stiff and still triggering--basically feels much worse than before the shot. (I am a woman 69, 122 lbs., no related medical history.)