No. Once DCFS receives a report of abuse or neglect, it is required by law to investigate. Neither the reporter nor the family can call it off.
You can tell the investigator what you believe actually happened — that you overreacted, that it was self-defense, or that it was a mutual confrontation. But recanting a report that was truthful can expose you to criminal charges, so be careful.
DCFS also does not drop an investigation because the reporter or the child turns 18 while the case is open.