DCFS records and juvenile court child-abuse records are sealed from the general public. An unfounded investigation usually will not affect an ordinary job application.
There are important exceptions. Government positions and jobs working with children involve deeper checks, and a DCFS finding can appear in those screenings.
Any related misdemeanor or felony case is different — that shows on a criminal record. If the criminal case was dismissed, an expungement attorney can help you clear it.