This is Dr. David
antibiotics don't knock at your immune system
they help your immune system get rid of bacterial infections in your body
if you have a bacterial sinus infection, the antibiotics will help
you feel like a new man because of the steroid injection, this will eventually wear off
signs of a bacterial sinus infection can be sinus tenderness, sinus congestion, headaches, dizziness.
it sounds like you could have a viral or bacterial sinus infection.
if you do take the antibiotic, you should take a probiotic pill daily with it to help add good bacteria into your bowels so you don't get diarrhea.
you should start taking it now since you had an antibiotic shot.
I hope you feel better
let me know if you have other questions.