Replace detected square with drawable image using opencv in java android

I am trying to make an AR tattoo demo app which can show tattoo on hand after user draw square on his/her hand. I tried square detection and also did GaussianBlur over detected square on hand. This things are working but how can I replace that detected part with my own tattoo image so user can see AR tattoo on his/her hand.

Here is my code :

public class MainActivity extends AppCompatActivity implements CameraBridgeViewBase.CvCameraViewListener2 {

    CameraBridgeViewBase cameraBridgeViewBase;
    BaseLoaderCallback baseLoaderCallback;
    Mat bwIMG, hsvIMG, lrrIMG, urrIMG, dsIMG, usIMG, cIMG, hovIMG;
    MatOfPoint2f approxCurve;
    int threshold;
    RelativeLayout imageslayout;
    ImageView imageView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageView = new ImageView(MainActivity.this);
        imageslayout = findViewById(R.id.imageslayout);
        threshold = 100;
        cameraBridgeViewBase = (JavaCameraView) findViewById(R.id.cameraViewer);
        cameraBridgeViewBase.setVisibility(SurfaceView.VISIBLE);
        cameraBridgeViewBase.setCvCameraViewListener(MainActivity.this);
        baseLoaderCallback = new BaseLoaderCallback(MainActivity.this) {
            @Override
            public void onManagerConnected(int status) {
                switch (status) {
                    case LoaderCallbackInterface.SUCCESS:
                        bwIMG = new Mat();
                        dsIMG = new Mat();
                        hsvIMG = new Mat();
                        lrrIMG = new Mat();
                        urrIMG = new Mat();
                        usIMG = new Mat();
                        cIMG = new Mat();
                        hovIMG = new Mat();
                        approxCurve = new MatOfPoint2f();
                        cameraBridgeViewBase.enableView();
                        break;
                    default:
                        super.onManagerConnected(status);
                        break;
                }
            }
        };
    }

    @Override
    public void onCameraViewStarted(int width, int height) {
    }

    @Override
    public void onCameraViewStopped() {
    }

    @Override
    public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
        Mat gray = inputFrame.gray();
        Mat dst = inputFrame.rgba();
        Imgproc.pyrDown(gray, dsIMG, new Size(gray.cols() / 2, gray.rows() / 2));
        Imgproc.pyrUp(dsIMG, usIMG, gray.size());
        Imgproc.Canny(usIMG, bwIMG, 0, threshold);
        Imgproc.dilate(bwIMG, bwIMG, new Mat(), new Point(-1, 1), 1);
        List<MatOfPoint> contours = new ArrayList<>();
        cIMG = bwIMG.clone();
        Imgproc.findContours(cIMG, contours, hovIMG, Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_SIMPLE);
        for (MatOfPoint cnt : contours) {
            MatOfPoint2f curve = new MatOfPoint2f(cnt.toArray());
            Imgproc.approxPolyDP(curve, approxCurve, 0.02 * Imgproc.arcLength(curve, true), true);
            int numberVertices = (int) approxCurve.total();
            double contourArea = Imgproc.contourArea(cnt);
            if (Math.abs(contourArea) < 100) {
                continue;
            }
            if (numberVertices >= 4 && numberVertices <= 6) {
                List<Double> cos = new ArrayList<>();
                for (int j = 2; j < numberVertices + 1; j++) {
                    cos.add(angle(approxCurve.toArray()[j % numberVertices], approxCurve.toArray()[j - 2], approxCurve.toArray()[j - 1]));
                }
                Collections.sort(cos);
                double mincos = cos.get(0);
                double maxcos = cos.get(cos.size() - 1);
                if (numberVertices == 4 && mincos >= -0.1 && maxcos <= 0.3) {
                    setLabel(dst, "X", cnt);
                }
            }
        }
        return dst;
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (cameraBridgeViewBase != null) {
            cameraBridgeViewBase.disableView();
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        if (!OpenCVLoader.initDebug()) {
            Toast.makeText(getApplicationContext(), "There is a problem", Toast.LENGTH_SHORT).show();
        } else {
            baseLoaderCallback.onManagerConnected(BaseLoaderCallback.SUCCESS);
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (cameraBridgeViewBase != null) {
            cameraBridgeViewBase.disableView();
        }
    }

    private static double angle(Point pt1, Point pt2, Point pt0) {
        double dx1 = pt1.x - pt0.x;
        double dy1 = pt1.y - pt0.y;
        double dx2 = pt2.x - pt0.x;
        double dy2 = pt2.y - pt0.y;
        return (dx1 * dx2 + dy1 * dy2) / Math.sqrt((dx1 * dx1 + dy1 * dy1) * (dx2 * dx2 + dy2 * dy2) + 1e-10);
    }

    private void setLabel(final Mat im, String label, MatOfPoint contour) {
        int fontface = Core.FONT_HERSHEY_SIMPLEX;
        double scale = 3;
        int thickness = 3;
        int[] baseline = new int[1];
        Size text = Imgproc.getTextSize(label, fontface, scale, thickness, baseline);
        final Rect r = Imgproc.boundingRect(contour);
        final Point pt = new Point(r.x + ((r.width - text.width) / 2), r.y + ((r.height + text.height) / 2));

        Mat mask = im.submat(r);
        Imgproc.GaussianBlur(mask, mask, new Size(55, 55), 55); // or any other processing
        Imgproc.putText(im, label, pt, fontface, scale, new Scalar(255, 0, 0), thickness);
    }
}

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