Jerome took a whack to the face and jaw from Chris Barker at Derby County with the FA Cup tie finely poised at 1-1.
But, with all Blues substitutes used, he opted to soldier on for the remaining ten minutes or so of normal and added time.
Blues nabbed a dramatic winner through Liam Ridgewell to book their passage into the quarter-finals.
He told the Birmingham Mail: "I got an elbow in the jaw. It was a poor challenge to be fair. I was looking at the ball and he caught me square in the jaw. I went into a bit of a daze, just the shock of it. I wanted to stay on, even if it was just to make a nuisance of myself as a body.
"Tim Williamson the physio said I should come off. I was on the sideline and couldn't really see much. I didn't know what was going on too much. I just thought I'd give it a go anyway. I grinded through it for a couple of minutes and tried to get around the pitch.
"It wasn't nice getting a blow like that, but it's part and parcel of football. Plenty of people have been in the same boat and carried on having got a crack on the head or jaw.
"At least we got through. I didn't want to let the boys down."