Usually your level on JudgeApps is updated at the same time as your level in Judge Center. That usually gets updated when the status of your certification review becomes “Approved.” You should receive a pair of emails at that time.
Nicola is correct. The certifying judge should normally update the level in Judge Apps as soon as they have completed the test. The review and Judge Center level might happen later (although please be prompt on your reviews!).
As others have mentioned, if you feel it as urgent, you can contact your regional coordinator. Actually, there is a form to do that directly here on JA. Go to feedback and select “Level Update Request”.
My judge level on Judge Center has already updated, along with the review and the pair of emails. It just hasn't updated on JudgeApps yet. I've used the feedback form, so hopefully that should sort it out.