Custom Health bar GUI that floats above players, how can i fix it?

t's been awhile since i've touched this script, but it's not even working. There's no errors, so i believe i'm doing this wrong. Anyways, to explain it briefly: ( BTW, it's in PlayerGui ) Basically, it creates a ScreenGui, and the script creates a BillboardGui that floats on top of it's head. (By putting it in their ScreenGui and setting the Adornee.)

Anyways, here's the script

local HealthBarGui = Instance.new("ScreenGui",script.Parent)
HealthBarGui.Name = "HealthBar"

function distanceAppear(plr1,plr2)
    while true do
    local plrname = plr1.Name
    if (plr1.Character.Head.Position - plr2.Character.Torso.Position).magnitude > 30 then
        local plrGUI = plr1.PlayerGui.HealthBar[plrname]
        plrGUI.HP.Visible = false
    else
        local plrGUI = plr1.PlayerGui.HealthBar[plrname]
        plrGUI.HP.Visible = true
    end
    wait()
    end
    return plr1,plr2
end

function grabplayers(plr)

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

    if player.Character and plr.PlayerGui.HealthBar:FindFirstChild(Playername)== nil then
        local Billboard = Instance.new("BillboardGui",HealthBarGui)
        Billboard.Name = player.Name        
        Billboard.Adornee = player.Character.Head
        Billboard.AlwaysOnTop = true
        Billboard.Size = UDim2.new(1,0,1,0)
        Billboard.Enabled = true
        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")
        distanceAppear(player,plr)

    end

    end
end

function GetPlayersFromGui(GUI)
    for i = 1, #GUI do
        GUI[GUI[i]] = true
    end
end

function Checkingfunc(plr1)

    script.Parent:WaitForChild("HealthBar")
    local GUIers = GetPlayersFromGui(plr1.PlayerGui.HealthBar:GetChildren())
    if GUIers ~= nil then
    for i, player in ipairs (game.Players:GetPlayers()) do
            local match = GUIers[player.Name]
            if not match then
                grabplayers(plr1)
            end
    end
    end
end

local localplayer = script.Parent.Parent
while true do
    Checkingfunc(localplayer)
    wait()
end