Making a health bar in a test game. I've tried for hours to fix it, but nothing works?

I have been working on this script for a while, and it is very bug. If anyone can, help refine it while you help answer this question.

I am trying to make a health check to make sure the health bar I'm making is working properly. If it is not, the health check will correct it. here is the health check portion. I'm still not sure exactly what to do, so it is unfinished.

local Dummy = game.Workspace.Dummy
local hp = Dummy.Humanoid
if game.Workspace.Dummy.Health -- INSERT FIX OR SOMETHING HERE
then


	function newHealth()
		script.Parent:TweenSize(UDim2.new(0,647,0,70))
	    script.Parent:TweenSize(UDim2.new(newHealth/500,0,1,0),Enum.EasingDirection.Out,Enum.EasingStyle.Quad,0.15)
	    script.Parent:TweenSize(UDim2.new(newHealth/300,0,1,0),Enum.EasingDirection.Out,Enum.EasingStyle.Quad,0.15)	
	end
end

Here is the rest of the code in case you need it.

wait (.1)
function reDummy ()
	local z = game.Workspace.Dummy

local backup = z:clone()

	wait(5)
	if z.Humanoid.Health == 0 then
		z:Remove()
		wait(6)
		backup.Parent = game.Workspace
		backup.Head:MakeJoints()
		backup.Torso:MakeJoints()
	end
	if z == nil then
		wait(9)
		backup.Parent = game.Workspace
		backup.Head:MakeJoints()
		backup.Torso:MakeJoints()
	end 
end

	local visible = script.Parent.Parent.Parent.Visible	
	local bframe = script.Parent.Parent.Parent.Parent
	while true do
		local Dummy = game.Workspace.Dummy
		local hp = Dummy.Humanoid
		
		
    script.Parent:TweenSize(UDim2.new(hp,0,1,0),Enum.EasingDirection.Out,Enum.EasingStyle.Quad,0.15)
    wait (0.1)
	local hp = Dummy.Humanoid.Health
    if hp < 0.001 or hp == 0 then
	print "it died"
        bframe.BaseFrame.Visible = false
    wait (7)

Dummy.Humanoid.HealthChanged:Connect(function(newHealth)
	    script.Parent:TweenSize(UDim2.new(0,647,0,70))
	    script.Parent:TweenSize(UDim2.new(newHealth/500,0,1,0),Enum.EasingDirection.Out,Enum.EasingStyle.Quad,0.15)
	    script.Parent:TweenSize(UDim2.new(newHealth/300,0,1,0),Enum.EasingDirection.Out,Enum.EasingStyle.Quad,0.15)
	end)
        bframe.BaseFrame.Visible = true
	        script.Parent:TweenSize(UDim2.new(0,647,0,70))
	        script.Parent:TweenSize(UDim2.new(hp,0,1,0),Enum.EasingDirection.Out,Enum.EasingStyle.Quad,0.15)
	        local hp = game.Workspace:WaitForChild("Dummy").Humanoid.Health/300
	        script.Parent:TweenSize(UDim2.new(hp,0,1,0),Enum.EasingDirection.Out,Enum.EasingStyle.Quad,0.15)
	    end
	    wait (.2)
	end