No one can hear me through the microphone, Only through speakerphone?

No one can hear me through the microphone, Only through speakerphone?

I have an iphone 4. I recently replaced the back glass from cracked after dropping it. It worked fine. Then 1 week later a baseball hit it at a baseball game (inside a otterbox case) Phone backglass cracked again at rear camera area. Now no one can hear me talk in a call unless I am on speakerphone.