Why does my swordscript break?

So basically I am trying to script a sword to have more damage then normal but every time I change a sword's damage the sword stops working completely. Why?

This is the Script:

and also the places I change the damage was the local damage from 5 to 10, the slash damage from 10 to 20, and the lunge damage from 30 to 60.

r = game:service("RunService")

multiplier=1

local damage = 10                                                                          


local slash_damage = 20
local lunge_damage = 60

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


local SlashSound = Instance.new("Sound")
SlashSound.SoundId = "rbxasset://sounds\\swordslash.wav"
SlashSound.Parent = sword
SlashSound.Volume = .7

local LungeSound = Instance.new("Sound")
LungeSound.SoundId = "rbxasset://sounds\\swordlunge.wav"
LungeSound.Parent = sword
LungeSound.Volume = .6

local UnsheathSound = Instance.new("Sound")
UnsheathSound.SoundId = "rbxasset://sounds\\unsheath.wav"
UnsheathSound.Parent = sword
UnsheathSound.Volume = 1


function blow(hit)
    if (hit.Parent == nil) then return end -- happens when bullet hits sword

    local humanoid = hit.Parent:findFirstChild("Humanoid")
    local plr2=game.Players:playerFromCharacter(hit.Parent)
    local vCharacter = Tool.Parent
    local vPlayer = game.Players:playerFromCharacter(vCharacter)
    local hum = vCharacter:findFirstChild("Humanoid") -- non-nil if tool held by a character
    if humanoid~=nil and humanoid ~= hum and hum ~= nil and plr2~=nil then
        -- final check, make sure sword is in-hand
        local right_arm = vCharacter:FindFirstChild("Right Arm")
        if (right_arm ~= nil) and plr2.TeamColor~=vPlayer.TeamColor then
            local joint = right_arm:FindFirstChild("RightGrip")
            if (joint ~= nil and (joint.Part0 == sword or joint.Part1 == sword)) then
                tagHumanoid(humanoid, vPlayer)
                humanoid:TakeDamage(damage*multiplier)
                wait(1)
                untagHumanoid(humanoid)
            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 anim = Instance.new("StringValue")
    anim.Name = "toolanim"
    anim.Value = "Slash"
    anim.Parent = Tool
end

function lunge()
    damage = lunge_damage

    LungeSound:play()

    local anim = Instance.new("StringValue")
    anim.Name = "toolanim"
    anim.Value = "Lunge"
    anim.Parent = Tool


    force = Instance.new("BodyVelocity")
    force.velocity = Vector3.new(0,10,0) --Tool.Parent.Torso.CFrame.lookVector * 80
    force.Parent = Tool.Parent.Torso
    wait(.25)
    swordOut()
    wait(.25)
    force.Parent = nil
    wait(.5)
    swordUp()

    damage = slash_damage
end

function swordUp()
    Tool.GripForward = Vector3.new(-1,0,0)
    Tool.GripRight = Vector3.new(0,1,0)
    Tool.GripUp = Vector3.new(0,0,1)
end

function swordOut()
    Tool.GripForward = Vector3.new(0,0,1)
    Tool.GripRight = Vector3.new(0,-1,0)
    Tool.GripUp = Vector3.new(-1,0,0)
end

function swordAcross()
    -- parry
end


Tool.Enabled = true
local last_attack = 0
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

    t = r.Stepped:wait()

    if (t - last_attack < .2) then
        lunge()
    else
        attack()
    end

    last_attack = t

    --wait(.5)

    Tool.Enabled = true
end


function onEquipped()
    UnsheathSound:play()
end


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


connection = sword.Touched:connect(blow)