I found this tut intrsting & simple.Source: http://www.newtutorials.com/ - Step 1 Open the picture that you would like to use for this tutorial - Step 2 Open your layers palette from Window > Layers and create a second layer. Now take your Lasso tool and make a circular outline of where you want the blood to be as displayed on the image. - Step 3 Fill the area selected with the lasso in a dark red color and select the layer as Color Burn on your layers palette. Deselect the selected area if you haven't done so yet. - Step 4 Now head over to your Tool bar and pick the smudge tool. Be sure the brush size for it is rather small. - Step 5 With the smudge tool, smudge the blood down until it looks closer to being realistic. - Step 6 Select the Burn tool, located to the right of the smudge tool on your Tool bar. - Step 7 With the burn tool, deepen the blood wound by making it darker on the critical spots which should be the middle. Take a look at my image to see how I did it. - Step 8 Finally, go to Filter > Texture > Texturizer. Once the box opens up, select Burlap for your Texture. Scale it to 200%. Give it a Relief of 2 or 3. Now press OK and you are done! Take a look at the final product. Also see here for a different version of the tutorial.The final pic looks more realistic.