Touched Script Stops Working After A While?

Hi! i have made a script which detects if a tool has touched a part, However, after a couple scans. The part no longer changes the text. Any work around for this? Any help is great, thanks in advance! Script:

local db = false
script.Parent.Touched:Connect(function(hit)
    if not db then
        db = true
    local h = hit.Parent.Name
    if h == "milk" then
            script.Parent.Parent.screen.SurfaceGui.Frame.TextLabel.Text = "Error, cannot purchase. Try again."
            wait(5)
            script.Parent.Parent.screen.SurfaceGui.Frame.TextLabel.Text = "Scan item >"
            db = false
       end
    end
end)