Read the angle from a 360-degree meter

I have a meter that I have managed to extract using openCV . The white in the middle of the image of the meter in different positions is the needle, which can go from 0 to 360.

my code:

void readAngleOfMeter(Mat image, int number)
{
    cvtColor(image, image, COLOR_BGR2GRAY);
    inRange(image, Scalar(255, 255, 255), Scalar(255, 255, 255), image);

    vector<Vec2f> lines;
    HoughLines(tmp, lines, 1, CV_PI / 360, 30, 0, 0);

    if (lines.size() == 0) {
        cout << "No lines found" << endl;
        return;
    }

    float thetasum = 0;
    for (size_t i = 0; i < lines.size(); i++)
    {
        float theta = lines[i][1];
        thetasum += theta;
    }
    thetasum = thetasum / static_cast<int>(lines.size());
    cout << "Theta " << thetasum << endl;
}

My problem is now that I want to read the angle of the meter. So I thought about using the average angle of each line, but the problem is that it doesn't work because a line can be interpreted in two ways (eg 90 is the same as 270) and from 360 to 0.

Any ideas?