Face Tracking using openCV is not working accurately

I want to detect face points and add mask on the face using openCV in unity (to make cross-platform app - android & iOS) “dlib Face Detection” is not being useful. Worked on sample project : https://assetstore.unity.com/packages/templates/tutorials/facetracker-example-35284 Eye rays is working properly in this project but the red face mask rotation is not proper. And even the face points are sometimes smaller than the face and sometimes larger (tried in iphone X). Is there any other website/document that I can follow for reference ? Or any other library that i can use ? Thanks in advance.