HP BillboardGUI on players?

Well, recently, I've been trying to script something that involves putting a custom Health GUI on top of player's heads, that, and a bit of practice to learn how other GUI's work. Unless there's a better idea how to do this, i'll just do it in this manner because once the other players distance from the GUI, the GUI becomes invisible to them.

function grabplayers(plr)
    for i, player in ipairs (game.Players:GetPlayers()) do
    local Playername = player.Name

    if player.Character and plr.PlayerGui:FindFirstChild(Playername)== nil then
        local Billboard = Instance.new("BillboardGui",plr.PlayerGui)
        Billboard.Name = player.Name        
        Billboard.Adornee = player.Character.Head
        local clonehpthing = player.PlayerGui.ScreenGui.HP:Clone()
        clonehpthing.Parent = Billboard
        clonehpthing.Position = UDim2.new(0,0,0,0)
        clonehpthing.Size = UDim2.new(0,130,0,10)
        clonehpthing.Health:Destroy()
        clonehpthing.BorderSizePixel = 1
        print ("It finally works")
    end

    end
end

function distanceAppear(player)
    for i, plr in ipairs (game.Players:GetPlayers()) do
    local plrname = plr.Name
    if (plr.Character.Head.Position - player.Character.Torso.Position).magnitude > 30 then
        local plrGUI = player.PlayerGui[plrname]
        plrGUI.HP.Visible = false
    else
        local plrGUI = player.PlayerGui[plrname]
        plrGUI.HP.Visible = true
    end
    end
end

game.Players.PlayerAdded:connect(grabplayers,distanceAppear)

There's no errors in the output, but i think i wrote the script a bit wrong. Also, if there's anything missing (Specifications, etc) i'll add more details (That is, if I can and it's relatable to the problem.)

Oh yeah, and the script is in Workspace

EDIT: The GUI is there (As demonstrated by typing game.Players.Username.PlayerGui.OtherUser.Name) And the HP object is there too. However, when i write: game.Players.Username.PlayerGui.OtherUser.HP.Visible = true , nothing happens, and HP is clearly there, showing no errors in the command.