Thank you for the opportunity to answer your question. I am sending this answer to you only a few minutes after you submitted your question.
That can be a tricky matter. Child abuse accusations made through Child Protective Services are generally kept confidential. While this places the accused in a bad position, the policy behind such confidentiality is to ensure that people are not afraid to or dissuaded from reporting suspected child abuse. However, if an accuser can be ascertained, the victim of false accusations may have a basis for a civil suit against the accuser for defamation and/or malicious prosecution or abuse of process. Such suits are complex and legal representation is important for such purposes.
A criminal complaint is also a possibility, as filing false reports is a crime. That said, for the same confidentiality policy would generally apply and, for the same reason, the state may be hesitant to pursue criminal charges against a false accuser unless it's very, very clear that the accusations were known to be false when made. An individual can file a criminal complaint directly with law enforcement officers. That said, when accused of a crime, speaking with law enforcement is dangerous because dangerous admissions can sometimes be made, even if an individual did not commit the alleged crime. Sometimes, seemingly innocent statements of an innocent person can be twisted and used against the person. Therefore, when filing a false reporting complaint, it's important to have one's attorney present to make sure no damaging statements are made.