Instead of making mask you can just apply adjustment layer as a clipping layer.

Step 16

Now it is time to add some texture to our image, but before we will do so, we need to create some basic custom brush that will fill our expectations.
Create new document with about 300px by 300px in size. Grab the brush tool with very small, hard round brush and paint around on the document with black color- also, use different brush sizes like 3 to 8 pixels. Try to achieve a big shape of dot that is created from small points.

Tip: There are two simple ways to easily change the brush size. First of them- on the keyboard hit the ‘[‘ and ‘]’ key to resize brush. One click means one pixel. You can hold button so the size will jump very fast. Second one is even simpler, but I mostly use it in digital painting. While you have brush tool active, hold [alt] button, then click and hold right mouse button. Now, when you have still both buttons held, move your cursor to the left and to the right. See? Now you can change the brush size very fast and very intuitive without getting into brush options.

When you think you have done the job well, you can save you work as a custom brush. To do that, go to Edit > Define Brush Preset, input the name and hit OK. Newly created brush is now added to your active brush set. You don’t have to save this file so just close it.

Our brush is pretty useless for now, but we will enhance it a bit. All you have to do is just applying these settings to your new custom brush:

Click on this icon...

... so your settings will be saved as a new brush.

Step 17

Create new clipping layer in between vibrance and Layer 5. Choose some very dark color, could be even black and brush the egg around (set brush size to about 200-240px)...

...so you get something like this:

Now change this layer’s opacity to about 5-10% and blending mode to Multiply. And it should looks like this:

Step 18

We are continue with our texture. Create new layer on top of previous one:

Choose some semi-dark color like #7e3b0b. Now it’s time to play with brush. Change dynamically brush size in range from 90px to even 500px and brush opacity from 9% to 30%. I see that I have to change my layer’s opacity to 50%, but it could be different your document. It depends how long you have brush around. I think it should looks good with the blending mode of layer set to Multiply. Here is how it looks like in my image: