I can almost say for sure that Ironite did not kill your lawn. Your lawn is most likely suffering from fungal disease(s) brought on by this extended period of excessively hot and humid weather. Some fungal diseases will kill your grass blades, but not the whole plant, and it will regrow in the fall, while others can kill the whole plant. Brown patch, the most prevalent disease right now, is foliar only, and if it doesn't affect your grass crowns, you should be ok.

Agree with tiemco.

Then it could be a coincidence, it's weird that if it's fungas (brown patch) my house is the only one that's getting it.

I just called scott lawn services and have them coming over for a estimate.

I water it more often for the last 1 week or so because I thought the area look very dry, and it has gotten worse and worse by the day.

Moisture and heat make fungus very happy. Take a close look at your grass blades and check for lesions to determine if it is a fungus or not (google for "brown patch images and discription"), but I'm confident that the iron is not the culprit.