When this script runs, the message doesn't clear. Why does it not clear?

local t = script.Parent
local h = t.Handle
local d = true

h.Touched:connect(function(hit)
    local n = t.Parent
    local character = hit.Parent
    local hu = character:FindFirstChild("Humanoid")
    local to = n:FindFirstChild("Torso")
    if hu and n and d == true and d ~= false then
        local e = Instance.new("Explosion")
        local m = Instance.new("Message")
        m.Name = "a"
        m.Parent = game.Workspace
        m.Text = "ALLAH AKBAR"
        e.Parent = game.Workspace
        e.Position = to.Position
        d = false
        wait(3)
        m:Destroy()
        d = true        
    end
end)

The Explosion works and the message works but the message does not go away.