im trying to enable mouse movement in fp when key pressed?

my game is based out of first person and im trying to enable mouse movement in first person when the key m is pressed and after key m is pressed again the mouse will stop movement and beome disabled heres my code

local UserInputService = game:GetService("UserInputService")


while true do
    UserInputService.MouseIconEnabled = false

    function onKeyPress(actionName, UserInputState, input0bject)
        if UserInputState == Enum.UserInputState.Begin then
            UserInputService.MouseIconEnabled = true
            UserInputService.ModalEnabled = true
        end
    end
end

game.ContextActionService:BindAction("KeyPress", OnKeyPress, false, Enum.KeyCode.M)

UPDATE: the code is working now but i still cannot enable the movement of my mouse however i now have it when the mouse icon is enable it does not disable it self when clicked or it will not appear when m is pressed?

local UserInputService = game:GetService("UserInputService")
UserInputService.MouseIconEnabled = false
UserInputService.InputBegan:Connect(function(input)
    if input.KeyCode == Enum.KeyCode.M then
        UserInputService.MouseIconEnabled = true
        --if UserInputService.MouseIconEnabled == true then
            --UserInputService.MouseIconEnabled = false
        end
    end
end)

there is nothing in the output currently?