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)