Yes, just leave it. How much confirmation do you need? BTW which lens is this? Some lenses seem to be more prone to dust than others. If it gets to be a problem, bring it to the service center. If you're feeling adventurous, take it apart yourself (there's a site somewhere showing how to take apart a Canon 17-55mm for cleaning, for example). I don't recommend it, but you could try.
sometimes in fixing a certain null problem, you create other problems which might actually affect your life. right now, it does not affect you, and it will not aggravate into something which will affect you. so why bother?
Dust on the front element and lens interior does not show up in pictures. However, it does scatter the incoming light a bit and contribute slightly to flare and image degradation. Dust also gets into the focusing mechanism which shortens the operating life of the lens. However, unless you shoot regularly in high dust environments, like deserts, or your lens is over a decade old, the dust should not be a problem.