Composition: I like the position of the lizard in the frame, she is in her environment, and you can see all the way to her tail that curves the eye deep into the photo. Fortuitous that she seemed to pose for you.
Technical: I am bothered by the dithering/noise in the photo overall. I wonder if this is an issue with the dof .. did you use macro? It must have been pretty dark to have to use 1/20 and f3.5. ISO 800? Yup. Must have been dark. Maybe that is the cause of the noise too. She is otherwise clear and detailed, but I think if you could have used a tripod and a smaller aperature, more of the body and tail would be clear too. Does this lizard move quickly?
Overall: This is a compelling image, and I think if the technical issues were cleared up, it may have scored higher.