what your periontist probably meant is that before the surgery your gums were inflammed, inflammation makes your gums swell. now that the surgery's been done and the inflammation has gone, the swelling has gone down, making it look as if your gums have shrunk, this sometimes happens after scaling (removal of calculus/tartar).
i don't think there's anything that can be done to make your gums grow,but there are prostheses that can be made to make appearance look better but a lot of patients don't like these and they pose hygiene problems which my exacerbate periodontal disease.
if you're worried, as always go back to the periodontist and have a chat and see what he can do
| 
After Gum Surgery 
Linear Mode
