How do I fix my sword dealing damage without clicking?

I'm creating a sword game, but the weapons are insta-killing other players just by touching the blade on them. Does anyone know how to fix it? This is the script for the sword:

r = game:service("RunService")


local damage = 0

local slash_damage = 0


sword = script.Parent.Handle
Tool = script.Parent


local SlashSound = Instance.new("Sound")
SlashSound.SoundId = "rbxasset://sounds\\woodmetal.ogg"
SlashSound.Parent = sword
SlashSound.Volume = .5

local secondSlashSound = Instance.new("Sound")
secondSlashSound.SoundId = "rbxasset://sounds\\grass2.ogg"
secondSlashSound.Parent = sword
secondSlashSound.Volume = 1

local debounce = false
function blow(hit)
	local humanoid = hit.Parent:findFirstChild("Humanoid")
	local vCharacter = Tool.Parent
	local vPlayer = game.Players:playerFromCharacter(vCharacter)
	local hum = vCharacter:findFirstChild("Humanoid")
	if humanoid~=nil and humanoid ~= hum and hum ~= nil then
	
	if debounce == false then
		debounce = true
		local right_arm = vCharacter:FindFirstChild("Right Arm")
		if (right_arm ~= nil) then
			local joint = right_arm:FindFirstChild("RightGrip")
			if (joint ~= nil and (joint.Part0 == sword or joint.Part1 == sword)) then
				tagHumanoid(humanoid, vPlayer)
					zomghit = 4
					humanoid:TakeDamage(zomghit)
				untagHumanoid(humanoid)
			end
		debounce = false
		end
	end


	end
end


function tagHumanoid(humanoid, player)
	local creator_tag = Instance.new("ObjectValue")
	creator_tag.Value = player
	creator_tag.Name = "creator"
	creator_tag.Parent = humanoid
end

function untagHumanoid(humanoid)
	if humanoid ~= nil then
		local tag = humanoid:findFirstChild("creator")
		if tag ~= nil then
			tag.Parent = nil
		end
	end
end


function attack()
	damage = slash_damage
	SlashSound:play()
	local vCharacter = Tool.Parent
	local hum = vCharacter:findFirstChild("Humanoid")
	blah = hum:LoadAnimation(script.Parent.Slash)
	blah:Play()
	hum.WalkSpeed = 0
	wait(.8)
	secondSlashSound:play()
	wait(.8)
	hum.WalkSpeed = 16
end

Tool.Enabled = true

function onActivated()

	if not Tool.Enabled then
		return
	end

	Tool.Enabled = false

	local character = Tool.Parent;
	local humanoid = character.Humanoid
	if humanoid == nil then
		print("Humanoid not found")
		return 
	end

	attack()

	wait(.5)

	Tool.Enabled = true
end


function onEquipped()
	if Tool.Handle.UnsheathSound.isPlaying == false then
		Tool.Handle.UnsheathSound:play()
	end
end

function onUnequipped()

	Tool.Handle.UnsheathSound:stop()

end

script.Parent.Activated:connect(onActivated)
script.Parent.Equipped:connect(onEquipped)
script.Parent.Unequipped:connect(onUnequipped)

connection = sword.Touched:connect(blow)

In attack() function, add variable that will be true when the player is attacking, and false after he attacks. Then in blow function you will have to check, if variable is set to true or false, if it's true, then it will do the script.