It depends, but usually a week to 2 weeks, but that isn't always the case. Just run your bloods a bit higher for a week and you should see an improvement. But hypo unawareness can also take longer to overcome dependant on how long you have been diabetic.
I sould say about 2 months but vrry often once control goes back to being tighter, then the awareness goes back to how it was So be tight enough to avoid complications but not to the point where awareness starts to be a problem
I agree with iHs, Donnellysdogs and Noblehead. It will take a good 6 - 8 weeks. Also be aware that if your control is too tight, you will end up where you started.