How long does it take for a yeast infection to clear up with a 1 day otc insert?

It depends: It depends on what one day drug was given, the severity of the infection, and whether or not this is a recurrent problem or not. One drug therapy does no always work under severe conditions.

Up to a week: It can take up to a week to totally eradicate the infection, however you should see your symptoms start clearing up much sooner that that; usually within the first few days. If it's not getting better, best to have it checked out to make sure that it truly is a yeast infection. Resistance to the OTC (and even the prescription) drugs is also possible, so seek care if it's not getting better.