First off, I have to say this one took me a little by surprise with comparison to the rest of your gallery, but, don't get me wrong, it's a great addition.
The angry clown is a common sight in most nightmares, and you've created the creepiness of it really well. The little details of the shadows and lighting are wonderful. Looking at it, I can see how accurate they are.
As many comments have suggested, the textures you use are fantastic. Your colors chosen are also neutral but nicely contrasting.
The only think I may have done differently is I may have had the background contrast a little more from the general golden skin color of the mask. To me, the colors seems to mesh too well, and it makes it difficult to keep my eyes on one long enough to check out all the details before being drawn to the next. But, regardless, this is real quality work. I'm happy to be following you.