Which version of Lightroom are you using?
What is the zoom level you are viewing your image at?
Library and develop modules don't show your images similarly.You will get best result in Develop module viewing your image at 100% zoom.
Please refer this detailed thread Develop module & library module aren't matching and let us know if that helps
Not totally unexpected, you should always view in Develop module at 1:1 for a precise view of these edits, especially sharpening on-screen.