"Reset" switch statement after value is equal

I'd like to run my switch and if/else statement again after the buttons are clicked three times in total.

The current pressed code is for three buttons with each 1 value. If those (current pressed code) are equal to the global string that contains a 3 number value, the picture box color will change to forest green. This is my code:

        switch ((sender as Button).Text)
        {

            case "1":
                serialMonitor.PrintLine("1");
                currentPressedCode = currentPressedCode + "1";
                break;
            case "2":
                serialMonitor.PrintLine("2");
                currentPressedCode = currentPressedCodeR + "2";
                break;
            case "3":
                serialMonitor.PrintLine("3");
                currentPressedCode = currentPressedCode + "3";
                break;
            default:
                break;
        }  if (buttonsPressed == 3)
        {
            if (currentPressedCode == vaultCode)
            {

                //vault open
                serialMonitor.PrintLine("vault");
                pcbGreen.BackColor = Color.ForestGreen;

            }
        }
        else
        {
            // wrong code
            serialMonitor.PrintLine("wrong");
            MessageBox.Show("Wrong password"); // wrong password messagebox
            pcbRed.BackColor = Color.DarkRed;
        }