The effect here is probably a bit too strong, but I thought it best to exaggerate it to make the difference clear.
The process is very simple. First duplicate the image (Ctrl+J).
If you want to try it on top of a multi-layered fx image without flattening everything, highlight the top layer and then press Shift + Ctrl + Alt + E to create a flattened copy of all the layers on top.
Change the Blend Mode of the new layer to Overlay, which will probably look pretty horrible, but worry not!
Go to Filter > Other > High Pass:
High Pass is very much easier than messing about with Filter > Sharpen and all the alternatives, so give it a try if you have never used it before.