Line 65, script not working? ')' expected (to close '(' at line 17) near 'end'

Since the function in line 17 is a Anonymous function it should have a closing parentheses after the end of that function. The error Message is basically telling you to add a closing parentheses for the function you created at line 17. I presume that function ends at line 47 so you'll need to change line 47 to end)

Your indentation is wrong, which makes the code confusing.
The problem here is that you've got one "end" too much, the one at line 47. Use this:

local mouse = game.Players.LocalPlayer:GetMouse()
local running = false
local Head = game.Workspace.Player.Head
local LeftArm = game.Workspace.Player["Left Arm"]
local LeftLeg = game.Workspace.Player["Left Leg"]
local RightArm = game.Workspace.Player["Right Arm"]
local RightLeg = game.Workspace.Player["Right Leg"]
local Torso = game.Workspace.Player.Torso

function getTool()  
    for _, kid in ipairs(script.Parent:GetChildren()) do
        if kid.className == "Tool" then return kid end
    end
    return nil
end

mouse.KeyDown:connect(function (key) -- DeadZone function
    key = string.lower(key)
    if string.byte(key) == 112 then
        running = true
        local keyConnection = mouse.KeyUp:connect(function (key)
            if string.byte(key) == 112 then
                running = false
            end
        end)
        for i = 1,5 do
            game.Workspace.CurrentCamera.FieldOfView = (70+(i*2))
            wait()
        end
        game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 64
        game.Players.LocalPlayer.Character.Humanoid.JumpPower = 150
        local s = Instance.new("Smoke")
        s.Parent = Torso
        s.Opacity = 0.3
        s.Size = 0.2
        local pl = Instance.new("PointLight", Torso)
        pl.Parent = Torso
        pl.Brightness = 20
        pl.Range = 10
        pl.Color = Color3.new(255, 51, 51)
        Head.Material = ("Neon")
        Head.BrickColor = BrickColor.new("Bright red")
        LeftArm.BrickColor = BrickColor.new("Bright red")
        LeftLeg.BrickColor = BrickColor.new("Bright red")
        RightArm.BrickColor = BrickColor.new("Bright red")
        RightLeg.BrickColor = BrickColor.new("Bright red")
        repeat wait (30) until running == false
        keyConnection:disconnect()
        game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 16
        game.Players.LocalPlayer.Character.Humanoid.JumpPower = 50
        s.Destroy()
        pl.Destroy()
        Head.Material = ("Plastic")
        Head.BrickColor = BrickColor.new("Pastel brown")
        LeftArm.BrickColor = BrickColor.new("Pastel brown")
        LeftLeg.BrickColor = BrickColor.new("Pastel brown")
        RightArm.BrickColor = BrickColor.new("Pastel brown")
        RightLeg.BrickColor = BrickColor.new("Pastel brown")
        for i = 1,5 do
            game.Workspace.CurrentCamera.FieldOfView = (80-(i*2))
            wait()
        end
    end
end)

Try this and let me know if it works :)

local mouse = game.Players.LocalPlayer:GetMouse()
local running = false
local Head = game.Workspace.Player.Head
local LeftArm = game.Workspace.Player["Left Arm"]
local LeftLeg = game.Workspace.Player["Left Leg"]
local RightArm = game.Workspace.Player["Right Arm"]
local RightLeg = game.Workspace.Player["Right Leg"]
local Torso = game.Workspace.Player.Torso

function getTool()  
    for _, kid in ipairs(script.Parent:GetChildren()) do
        if kid.className == "Tool" then return kid end
    end
    return nil
end

mouse.KeyDown:connect(function (key)) -- ADDED ANOTHER BRACKET HERE TO CLOSE THE ONE YOU OPENED
    key = string.lower(key)
    if string.byte(key) == 112 then
        running = true
        local keyConnection = mouse.KeyUp:connect(function (key)
            if string.byte(key) == 112 then
                running = false
            end
        end)
        for i = 1,5 do
            game.Workspace.CurrentCamera.FieldOfView = (70+(i*2))
            wait()
        end
        game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 64
        game.Players.LocalPlayer.Character.Humanoid.JumpPower = 150
            local s = Instance.new("Smoke")
            s.Parent = Torso
            s.Opacity = 0.3
            s.Size = 0.2
            local pl = Instance.new("PointLight", Torso)
            pl.Parent = Torso
            pl.Brightness = 20
            pl.Range = 10
            pl.Color = Color3.new(255, 51, 51)
            Head.Material = ("Neon")
            Head.BrickColor = BrickColor.new("Bright red")
            LeftArm.BrickColor = BrickColor.new("Bright red")
            LeftLeg.BrickColor = BrickColor.new("Bright red")
            RightArm.BrickColor = BrickColor.new("Bright red")
            RightLeg.BrickColor = BrickColor.new("Bright red")
        end
        repeat wait (30) until running == false
        keyConnection:disconnect()
            game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 16
            game.Players.LocalPlayer.Character.Humanoid.JumpPower = 50
            s.Destroy()
            pl.Destroy()
            Head.Material = ("Plastic")
            Head.BrickColor = BrickColor.new("Pastel brown")
            LeftArm.BrickColor = BrickColor.new("Pastel brown")
            LeftLeg.BrickColor = BrickColor.new("Pastel brown")
            RightArm.BrickColor = BrickColor.new("Pastel brown")
            RightLeg.BrickColor = BrickColor.new("Pastel brown")
        for i = 1,5 do
            game.Workspace.CurrentCamera.FieldOfView = (80-(i*2))
            wait()
        end
    end
end)