Ketchup Splatter splattering the wrong person?

Hello, so I have a script which is suppose to shoot a red ball of ketchup on left click, and the player it hits will be shown the splatter gui. Heres the code:

p = game.Players.LocalPlayer
mouse = p:GetMouse()
piws = workspace:WaitForChild(p.Name)
ws = piws.Humanoid.WalkSpeed
fov = workspace.Camera.FieldOfView

local function isInPlayer(part)
	local player = game.Players:GetPlayerFromCharacter(part)
	if player then
		return player
	elseif part.Parent ~= workspace then
		return isInPlayer(part.Parent)
	else
		return nil
	end
end

script.Parent.Equipped:connect(function(mouse)
	mouse.Button1Up:connect(b1up)
	mouse.Button2Down:connect(b2down)
	mouse.Button2Up:connect(b2up)
end)

function Touched(part)
	if isInPlayer(part) then
		repeat
			wait()
		until isInPlayer(part):FindFirstChild("PlayerGui")
		if not isInPlayer(part).PlayerGui.popups:FindFirstChild("ksplatter") then
			isInPlayer(part).leaderstats.Splats.Value = isInPlayer(part).leaderstats.Splats.Value + 1
			game.ReplicatedStorage.ksplatter:Clone().Parent = isInPlayer(part).PlayerGui.popups
		end
	end
end

function b1up()
	local ketchup = game.ReplicatedStorage.ketchupblob:Clone()
	ketchup.Parent = workspace
	ketchup.Position = Vector3.new(piws.Head.Position.x, piws.Head.Position.y + 2, piws.Head.Position.z)
	local bf = Instance.new("BodyForce")
	bf.Parent = ketchup
	bf.Force = Vector3.new(0, ketchup:GetMass() * workspace.Gravity * 0.8, 0)
	ketchup.Velocity = (mouse.hit.p - ketchup.Position).unit * 200
	ketchup.Touched:connect(Touched)
end

function b2down()
	fov = workspace.Camera.FieldOfView
	ws = piws.Humanoid.WalkSpeed
	piws.Humanoid.WalkSpeed = 5
	p.CameraMode = Enum.CameraMode.LockFirstPerson
	workspace.Camera.FieldOfView = 20
	mouse.Icon = "http://www.roblox.com/asset/?id=123566253"
end

function b2up()
	workspace.Camera.FieldOfView = fov
	piws.Humanoid.WalkSpeed = ws
	p.CameraMode = Enum.CameraMode.Classic
	mouse.Icon = "http://www.roblox.com/asset/?id=440124541"
end

script.Parent.Unequipped:connect(function()
	workspace.Camera.FieldOfView = fov
	piws.Humanoid.WalkSpeed = ws
	p.CameraMode = Enum.CameraMode.Classic
	mouse.Icon = "http://www.roblox.com/asset/?id=440124541"
end)

Sadly, the person shooting it is splattered, and the ball just goes right through the other player without it affecting them? All help is appreciated. :)

You can't mess with other player's PlayerGui through a LocalScript since it is not visible. You have to use a Script to do things like inserting a GUI into another Player.

Try copying a Script into the bullet with something like this inside of it:

script.Parent.Touched:connect(function(part)
   --Part got splatted! Do something!
end)