Face recognition using OpenCV or any other SDK?

I need to recognize faces in Unity. I have been able to detect faces using Unity but I am facing trouble doing the face recognition part. I am using this official OpenCV Unity asset.

I tried playing around with the different samples, but unfortunately, I am not being able to figure out where I am going wrong and stuck. Any help to achieve face recognition in Unity will be much appreciated.

Also, I need to deploy this to an Android phone.