That's a pretty good Jesse. My only advice would be to slightly reduce your 'sh' sound on the 's'.
As for working on it, you may already have heard this, but I'll give you the advice that has 1. made my impressions funnier and 2. I got from Billy West on a Futurama commentary so it's pretty damn worth it.
An impression doesn't have to be that accurate, as long as it's identifiable and funny. I think your Jesse does both of those jobs.
