First of, you should always save as .png unless you need to save space.
The grungy brush on her face makes her feel dirty, especially near her nose.
The render is low quality(check her hair on your right) and colors aren't saturated enough to match the rest of the image, sharpening the render a little and adjusting the colors would help.
Some bubbles are cut off and the various elements really don't blend together.
What i like is that the render has a 90's drawing vibe to it(like the render i used for my avatar), just remember to begin with an idea and don't go off road; also try to avoid to slap big elements on your focal point/render.