Just my opinion, but I would say no.
It's not a good look, professionally. At best, it shows you're nervous, which is understandable but you still have to be able to put nerves aside as you move through the publication process. You also risk giving the impression, rightly or wrongly, that you're going to be one of those authors who wants to make constant tweaks rather than follow an editing process. That could foreshadow more work for an agent down the line.
Chances are the agent has started reading already and has probably made it past the opening chapter anyway. Chances also are that whatever's making you unhappy with it is pretty minor, in the grand scheme of things.
In general, always make sure the MS is ship-shape before you query. If you want to make tweaks, wait until after a round of queries.