Prob Salesforce validation would be simplest
But if you want to do it on skuid, you can create a field validation , and add a formula that meets your criteria : exmaple: DATE_DIFF({{your_field}}, TODAY(), DAY)<1
or you can create similar formula in a UI-Field and disable save button if met
David is right on the various formula options, I would recommend doing it in Salesforce through a validation and through the Skuid UI. The validation is key to avoid issues with records created / updated outside of Skuid, but it could also be annoying for users to enter a value and save then find out it was wrong instead of knowing before they try to save.
I attached a page with a quick example of using formulas to control enabling a button.