Trying to make a sword that makes you Invisible when damaged, but also fires when healing (?)

Im trying to make a sword that makes you Invisible when damaged, currently It only makes your body parts (R6) Invisible, works but there Is a problem where It will activate the ability when healing but I want It to only work when damaged

Script:

local Tool = script.Parent
local SoundFolder = Tool.Sounds
local SlashAttack
local Boolens = {
    Debounce = false,
    CanDamage = false
}
local Animations = { ---Oh boi there Is alot
    EquipAnimation = Tool.EquipAnimation,
    Idle = Tool.Idle,
    Slash = Tool.Slash
}

Tool.Equipped:Connect(function()
    SoundFolder.Unsheath:Play()
    local Humanoid = Tool.Parent.Humanoid
    Humanoid.WalkSpeed = 20
    Tool.Handle.Transparency = 0.9
    Humanoid.Parent.Head.Transparency = 0.9
    Humanoid.Parent.Torso.Transparency = 0.9
    Humanoid.Parent["Left Arm"].Transparency = 0.9
    Humanoid.Parent["Right Arm"].Transparency = 0.9
    Humanoid.Parent["Left Leg"].Transparency = 0.9
    Humanoid.Parent["Right Leg"].Transparency = 0.9

    local EquipAnimationTrack = Humanoid:FindFirstChild("Animator"):LoadAnimation(Animations.EquipAnimation)
    EquipAnimationTrack:Play()
    task.wait(0.30)
    local Idle = Humanoid:FindFirstChild("Animator"):LoadAnimation(Animations.Idle)
    Idle:Play()
    Humanoid.HealthChange:Connect(function()
        Humanoid.WalkSpeed = 30
        Tool.Handle.Transparency = 1
        Humanoid.Parent.Head.Transparency = 1
        Humanoid.Parent.Torso.Transparency = 1
        Humanoid.Parent["Left Arm"].Transparency = 1
        Humanoid.Parent["Right Arm"].Transparency = 1
        Humanoid.Parent["Left Leg"].Transparency = 1
        Humanoid.Parent["Right Leg"].Transparency = 1
        wait(5)Humanoid.WalkSpeed = 20
        Tool.Handle.Transparency = 0.9
        Humanoid.Parent.Head.Transparency = 0.9
        Humanoid.Parent.Torso.Transparency = 0.9
        Humanoid.Parent["Left Arm"].Transparency = 0.9
        Humanoid.Parent["Right Arm"].Transparency = 0.9
        Humanoid.Parent["Left Leg"].Transparency = 0.9
        Humanoid.Parent["Right Leg"].Transparency = 0.9
    end)
    Tool.Unequipped:Connect(function()
        Humanoid.WalkSpeed = 16
        Tool.Handle.Transparency = 0.5
        Humanoid.Parent.Head.Transparency = 0
        Humanoid.Parent.Torso.Transparency = 0
        Humanoid.Parent["Left Arm"].Transparency = 0
        Humanoid.Parent["Right Arm"].Transparency = 0
        Humanoid.Parent["Left Leg"].Transparency = 0
        Humanoid.Parent["Right Leg"].Transparency = 0
        Idle:Stop()
    end)
end)


Tool.Activated:Connect(function()
    if not Boolens.Debounce then
        Boolens.Debounce = true
        Boolens.CanDamage = true
        SoundFolder.Slash:Play()
        print("The tool has been clicked")
        local Humanoid = Tool.Parent.Humanoid

        SlashAttack = Humanoid:FindFirstChild("Animator"):LoadAnimation(Animations.Slash)
        SlashAttack:Play()
        wait(1)
        Boolens.Debounce = false
        Boolens.CanDamage = false
    end
end)

Tool.Handle.Touched:Connect(function(hit)
    local Player = game:GetService("Players"):GetPlayerFromCharacter(hit.Parent)
    if Player then
        local player1 = game.Players:GetPlayerFromCharacter(Tool.Parent)
        local player2 = game.Players:GetPlayerFromCharacter(hit.Parent)

        if (player1 ~= nil) and (player2 ~= nil) then
            local humanoid = (player2.Character or player2.CharacterAdded:Wait()):FindFirstChildWhichIsA("Humanoid")

            if (player1.TeamColor ~= player2.TeamColor) then
                if (humanoid ~= nil) and Boolens.CanDamage == true then
                    Boolens.CanDamage = false
                    humanoid:TakeDamage(10)
                    humanoid.WalkSpeed = 10
                    humanoid.JumpPower = 30
                    wait(5)
                    humanoid.WalkSpeed = 16
                    humanoid.JumpPower = 50
                end
            end
        end
    else
        local NPCHumanoid = hit.Parent:WaitForChild("Humanoid")
        if NPCHumanoid and Boolens.CanDamage == true then
            Boolens.CanDamage = false
            NPCHumanoid:TakeDamage(10)
            NPCHumanoid.WalkSpeed = 10
            NPCHumanoid.JumpPower = 30
            wait(5)
            NPCHumanoid.WalkSpeed = 16
            NPCHumanoid.JumpPower = 50
        end
    end
end)

I believe it's because you're using Humanoid.HelathChange() (on line 31). To fix this, I would just make 2 variables to see the difference in health. Other than that, I do have a suggestion. I would do an in pairs() loop to set the transparency. (I marked all the places I used in pairs() as I made it into a function

-- Starting on line 13 in your script
local function setCharacterTransparency(characterModel, transparencyValue)
	if characterModel and transparencyValue then -- prevents script from breaking if not all parameters are given
		for _, object in pairs(characterModel)
			if object:IsA("BasePart") then -- checks to see if the child is a part (there is the humanoid, default scripts from roblox, animator, etc. that don't have a transparency value)
				object.Transparency = transparencyValue
			end
		end
	end
end

Tool.Equipped:Connect(function()
	SoundFolder.Unsheath:Play()
	local Character = Tool.Parent -- I added this variable for the in pairs() loop
	local Humanoid = Tool.Parent.Humanoid
	Humanoid.WalkSpeed = 20
	Tool.Handle.Transparency = 0.9
	setCharacterTransparency(Character, 0.9) -- in pairs() (much cleaner, right?)
	local EquipAnimationTrack = Humanoid:FindFirstChild("Animator"):LoadAnimation(Animations.EquipAnimation)
	EquipAnimationTrack:Play()
	task.wait(0.30)
	local Idle = Humanoid:FindFirstChild("Animator"):LoadAnimation(Animations.Idle)
	Idle:Play()
	local oldHealth = Humanoid.Health
	Humanoid.HealthChange:Connect(function()
		local newHealth = Humanoid.Health
		if newHealth < oldHealth then -- here, I check to see if the character's current health is lower than their health before
			Humanoid.WalkSpeed = 30
			Tool.Handle.Transparency = 1
			setCharacterTransparency(Character, 1) -- in pairs()
			wait(5)Humanoid.WalkSpeed = 20
			Tool.Handle.Transparency = 0.9
			setCharacterTransparency(Character, 0.9) -- in pairs()
		end
		oldHealth = newHealth -- make sure to reset variable (updating oldHealth)
	end)
	Tool.Unequipped:Connect(function()
		Humanoid.WalkSpeed = 16
		Tool.Handle.Transparency = 0.5
		setCharacterTransparency(Character, 0) -- in pairs()
		Idle:Stop()
	end)
end) -- Ending on line 60 in your script

If you'd like to add the tool transparency and walkspeed (Replace the setCharacterTransparency() function):

local function invisibilityToolFunction(characterModel, transparencyValue, walkSpeed, tool) -- change the function's name to be whatever you'd like
	if characterModel then
		if walkspeed then
			characterModel.Humanoid.WalkSpeed = walkSpeed
		end
		if transparencyValue then
			if tool then
				tool.Handle.Transparency = transparencyValue
			end
			for _, object in pairs(characterModel)
				if object:IsA("BasePart") then
					object.Transparency = transparencyValue
				end
			end
		end
	end
end