Wow! This is gorgeous! I don't see how you could be frustrated with this. The airbrushing is seamless in my humble, inexperienced, never-used-an-airbrush-before opinion.
I could see you going two ways with this. The first would be a woodcarving-type skin, which the colours (nice colours!) suggest. If that's the case, I would leave the background as is (an overly busy background would interfere with your beautiful vines and flowers anyway) or
you could texture the background in such a way that it looks chiseled, making every inch of the skin appear as if it was carved out of a large piece of wood.
The second would place more emphasis on the botanical front, in which case you could also leave the background as is, though you might want to add more colour. Or you could give the background a faint texture of vines/leaves . . . kind of a foresty backdrop.
Like the previous suggestions, I feel the frame needs to interact more with the curvy design it contains.