Why isn't my my exploding barrel script not working... ? (I hate that title requirement...)

I'm making a barrel that can explode, but it doesn't want to work no matter what I do. To make things more clear I'm using a normal script, Humanoid, Torso, Head

This is the script, nothing functions... :

Heater = script.Parent.Torso
Neon = script.Parent.Head
Humanoid = script.Parent.Humanoid
Fire = Heater.Fire
Smoke = Heater.Smoke

if Humanoid.Health <= 75 then
	Neon.BrickColor = BrickColor.new("Bright yellow")
end

if Humanoid.Health <= 50 then
	Neon.BrickColor = BrickColor.new("Orange")
	Fire.Enabled = true
end

if Humanoid.Health <= 25 then
	Neon.BrickColor = BrickColor.new("Crimson")
end

if Humanoid.Health == 0 then
	Exp = Instance.new("Explosion")
	Exp.BlastPressure = 100000
	Exp.BlastRadius = 7.5
	Exp.Parent = game.Workspace
	Exp.Position = Heater.Position
	Heater:Destroy()
	Neon:Destroy()
end

Hope you can find the error and help me fix it, please !

Your script only runs once when the game first starts. To make it update every time the player’s health is changed, you must check the health every time the property changes.

Heater = script.Parent.Torso
Neon = script.Parent.Head
Humanoid = script.Parent.Humanoid
Fire = Heater.Fire
Smoke = Heater.Smoke

Humanoid:GetPropertyChangedSignal("Health"):Connect(function()
	if Humanoid.Health <= 75 and Humanoid.Health > 50 then
  		Neon.BrickColor = BrickColor.new("Bright yellow")
	elseif Humanoid.Health <= 50 and Humanoid.Health > 25 then
   		Neon.BrickColor = BrickColor.new("Orange")
  		Fire.Enabled = true
	elseif Humanoid.Health <= 25 and Humanoid.Health > 0 then
		Neon.BrickColor = BrickColor.new("Crimson")
	elseif Humanoid.Health <= 0 then
	  	Exp = Instance.new("Explosion")
 		Exp.BlastPressure = 100000
	  	Exp.BlastRadius = 7.5
 		Exp.Parent = game.Workspace
	  	Exp.Position = Heater.Position
 		Heater:Destroy()
 		Neon:Destroy()
	end
end)