The Northern Ireland international returned to action wearing a protective mask just a fortnight after suffering a minor fracture of his skull.
Johnson said: "People are making me out as some sort of hero, but it is not about that. Once the bone was reset, the consultant was happy enough for me to play, and so that was good enough for me.
"I feel okay, and the cheekbone is all right."
Despite heavy pressure from the home side, particularly during the closing stages, Birmingham fought a tough rear-guard action to secure what could prove a vital point in their battle to stay out of the bottom three.
"The boys showed tremendous character to hang in there against a really top team," said Johnson, whose cheekbone may take up to six weeks to heal properly.
"But we have to be able to beat teams, which is something we are aware of and need to rectify.
"We need to do well against the teams around us.
"It is going to be tough finish - any of five or six teams could be involved in it.
"But the type of character we have shown, that is what is going to keep us up."
Blues boss Alex McLeish believes Johnson epitomises the "heart" which his squad will need to stay up.
"Damien is my type of player, that's for sure, to show that kind of bravery," said the former Scotland coach. "I know that many players would not have even contemplated playing with the problem he had, but he was a great leader for us.
"The medical team told me, when Damien had his mishap, that because the operation was successful, he should be back for Arsenal but that he would have to wear a mask. I was astonished with that, but the medical team have done a fantastic job.
"He's got the heart and the character to put his body on the line.