Custom Health Script help?

Anyone knows whats wrong with my custom health gui here my script:

local char = workspace:findFirstChild(script.Parent.Parent.Parent.Name)
hum = char.Humanoid
hum.Changed:Connect(function()
	script.Parent.Frame.Health.Frame.Size =UDim2.new(hum.Health/hum.MaxHealth,0,1,0)
	script.Parent.Frame.Text.TextLabel.Text = ""..hum.MaxHealth.."/"
if hum.Health <= hum.MaxHealth*0.90 then
	script.Parent.Frame.Health.Frame.BackgroundColor3 = Color3.new(150,0,0)

script.Parent.Frame.Health.Frame.BackgroundColor3 = Color3.new(0,170,0)
end  
end)
also heres my second script thats connected to the first one:

wait(1) 
script.Parent.HP.Disabled = false
anyone can tell meh whats wrong?

Wrap your code

When posting code, use code block to wrap your code. To do that, select your code with mouse and press the blue lua button when posting the question.

A better way to get character

local char = workspace:findFirstChild(script.Parent.Parent.Parent.Name)

Here, you are getting character by player's name. While this will work (Except if there is something in Workspace that is named the same as player), I would advise you to use this:

local char = script.Parent.Parent.Parent.Character

Update only if needed

You are also updating the gui no matter what changed in the Humanoid, which is unnecessary. You should check if changed property is Health (also MaxHealth if max health can be changed in the game)

hum.Changed:connect(function(property)
	if property == "Health" then
		-- code
	end
end)

Always check your tree if you referenced your objects correctly

Make sure that there is a gui object named 'Text' that is a child of Frame.

script.Parent.Frame.Text.TextLabel.Text = ""..hum.MaxHealth.."/"

Based on your code, I would say this is what you wanted unless 'Text' really is a gui object parented to Frame. And, you can't concatenate a string and number, so you should use tostring function.

script.Parent.Frame.Health.TextLabel.Text = ""..tostring(hum.MaxHealth).."/"

Make sure your logic is correct

Also, this code part seems not to do what you might have intended

if hum.Health <= hum.MaxHealth*0.90 then
	script.Parent.Frame.Health.Frame.BackgroundColor3 = Color3.new(150,0,0)
	script.Parent.Frame.Health.Frame.BackgroundColor3 = Color3.new(0,170,0)
end

You should add an else statement

if hum.Health <= hum.MaxHealth*0.90 then
	script.Parent.Frame.Health.Frame.BackgroundColor3 = Color3.new(150,0,0)
else
	script.Parent.Frame.Health.Frame.BackgroundColor3 = Color3.new(0,170,0)
end

Check if there is something else making it not work

And finally what does HP script do? It might be interfering with your script.

The full code

Adding fixes that @Programmix made, here is the full code.

local char = script.Parent.Parent.Parent.Character
local hum = char.Humanoid

hum.Changed:connect(function(property)
	if property == "Health" then
		script.Parent.Frame.Health.Frame.Size = UDim2.new(hum.Health/hum.MaxHealth,0,1,0)
		script.Parent.Frame.Health.TextLabel.Text = tostring(hum.Health).."/" ..tostring(hum.MaxHealth)
		if hum.Health <= hum.MaxHealth*0.90 then
			script.Parent.Frame.Health.Frame.BackgroundColor3 = Color3.new(150/255,0,0)
		else
			script.Parent.Frame.Health.Frame.BackgroundColor3 = Color3.new(0,170/255,0)
		end
	end
end)

wait(1)
script.Parent.HP.Disabled = false

We can't read your mind

Make your questions clear, give us any errors that occurred. It's hard to help when you don't give us a tree hierarchy of your gui. Also, I am not sure exactly what you want to achieve at some points of your code. I have assumed some things and I hope I understood you correctly.

I hope this helped.