Anything you paint on this layer will now have THAT style applied to it. You can even SAVE the Layer Style - give it a name you can remember, and use it later - just bring up the style whenever you wanna use those brushes.

Now here's the kicker - create a new layer above your "stitches" layer. Hold Alt/Option and click on the line between the stitches and new layer to LINK them. I used a fat green brush, but you should get the idea - anything you paint on the layer will only appear directly atop the filled pixels - NOT the Latyer Styles you see, but the actual filled pixels. This means you can go in and paint the stiches themselves, blood and meat within the open wound - you get the idea - and it won't spill out onto the rest of the canvas.

This means you can use the style to create all the outer effects, and even the bevel and emboss, and hand-paint the inside details.

Lemme know if you were looking for something else and I'll give you another tut.
Hope this helps-
-Lew ;-)