Here's the story:

One of my profs left for a month-ish long visiting professorship overseas two weeks before classes ended. Because he wasn't actually here, I had to hand in one of my assignments over e-mail (FWIW this paper was late, but I had already arranged to have an extension of sorts, because I was just not feeling very confident with the material yet). I sent it about a week and a half ago. He hasn't sent it back graded yet, which is ok, because 1 1/2 week isn't very long, but he also didn't even send a short confirmation e-mail (i.e. "Thanks, I got your paper"), which I think is reasonable (is it?). So now I'm worried that it may have gotten lost amidst the many e-mails he probably gets everyday.

For reference I know that he returned the assignments for the other students quite quickly (only 6 people in the class and he had them marked within 4 days). He is also a known flake. For example he forgot that he had scheduled a midterm, and showed up on the day without having written one.

So my main question is how long do I wait to send a follow up e-mail. Or do I just not bother him at all and trust that he received my assignment, and is just being his usual flaky self? I'm mostly worried because he's asked other students to revise theirs and if he will expect me to do the same I'm not sure I'll have time before the end of the term if I don't know soon! Part of me wants to just not bother him while he's off doing fun academic things in France, but the rest of me is like AHHHH!!!