How to make a projectile do splash damage?

So I have a projectile that fires and whenever it hits an object I want it to do splash damage.

local TweenService = game:GetService("TweenService")
local TI = TweenInfo.new(0.5, Enum.EasingStyle.Linear, Enum.EasingDirection.InOut, 0, false, 0)

local properties = {
   Size = Vector3.new(20, 20, 20),
   Transparency = 0.5
}

local properties2 = {
   Size = Vector3.new(0, 0, 0),
}

local Tween = TweenService:Create(script.Parent, TI, properties)
local Tween2 = TweenService:Create(script.Parent, TI, properties2)

script.Parent.Touched:Connect(function(hit)
    if hit.Parent.Name ~= script.Creator.Value then
        script.Parent.Anchored = true 
        script.Parent.CanCollide = false
        Tween:Play()
        script.Parent.Blast:Play()
        Tween.Completed:Connect(function()
            Tween2:Play()
            Tween2.Completed:Connect(function()
                script.Parent:Destroy()
            end)
        end)
    end
end)

This script works fine and it allows the projectile to have a tween whenever it hits something where it starts increasing in size and covers an area, but for some reason whenever it increases in size, it does not deal damage to sorrounding players, why is this? The damage script fires inside the projectile with a Touched function (there is nothing wrong with the damage script as it works fine when you directly attack a player with the projectile instead of attempting to use splash damage).