Thanks for contacting us. There are a couple of things you can try, however restoring noisy and grainy images is generally quite difficult to achieve. Within the Pro tab > Pro Editor tool > Pixlr Editor there is the Filter menu > Denoise option which would be the first thing to try.
You could also use some of Ribbet’s Touch-Up tools, such as Airbrush to smooth areas of high grain.
Let us know if we can be of any further assistance.