Can I get help with a CFrame head rotation script?

I have this much so far. I need to make the head rotate in the direction the player is looking. My problem is that I am not quite sure how to do this. I have tried to use the camera's CFrame properties. My problem is that I don't know how to put this into the script.

local tool = script.Parent
local player = game.Players.LocalPlayer
repeat wait() until player.Character
local char = player.Character
local head = char:WaitForChild("Head")
local mouse = player:GetMouse()
local torso = char:WaitForChild("Torso")

local equipped = false

local weld = Instance.new("Weld")


function equip()
	equipped = true
	while equipped == true do
		wait()
		weld.Parent = head
		weld.Part0 = head
		weld.Part1 = torso
		weld.C0 = CFrame.new(0, -1.5, 0) -- My problem begins here. I have the position of the head, now I need to have it constantly update the heads rotation in the direction of the camera.
	end
end

function unequip()
	equipped = false
end

tool.Equipped:connect(equip)
tool.Unequipped:connect(unequip)