This was done very well and I cannot stress enough that you are very skilled in human anatomy. The only thing that's really grabbing my attention is the mouth area. For future reference the bottom point of the nose should always be lined up with the crease in the feline lips. As you can probably see now that it doesn't line up therefore it doesn't look as natural as it could. As far as a background I don't believe that you need to change or modify it unless you aren't satisfied until you do so. I believe it compliments the character greatly without drawing attention away from the subject at hand.
My personal opinion would also be to move the canine tooth forward a bit because it looks too far back. Overall this is great piece and I love seeing you improve drawing by drawing ^^