How can I use photoshop elements to create a realistic looking scar?

I'm looking to edit some pictures of me and my friends, and want the additions to look real.How can I use photoshop elements to create a realistic looking scar?
Making a realistic looking scar in photoshop Cs4 would be very hard, and requires a lot of expertise. I would consider making one in photoshop elements impossible. Sorry man, but you can download a 30 day trial of photoshop Cs4 at Adobe's website (or here https://www.adobe.com/cfusion/tdrc/index鈥?/a> How would I go about making it in this program? I would start of by making a selection of how I want the scar to look, then fill that selection with a dark (maroon) red. Then I would reselect that selection, contract and feather it then fill it with a lighter red, but still very dark. I would keep doing that, until I have a graduating dark red ';mountain'; then I would use the dodge and burn tool to make the ';ripples'; in the scar. You can also use the smudge tool to ad some ripples and crust. Remember to keep each layer of colour on separate layers so that you keep edibility. You can also add a bit of grain or noise to the layers to make the scar more crusty. And you can experiment with different blending modes, such as darken and multiply. I hope this helps you :D