SandraHi Risty,
Well, there could be a possibility that he is cushingoid. This would be caused by excessive medication. Things to look for are chipmunk cheeks, hump on the back of the neck, excessive weight gain. My son, at 3 months old, was cushingoid. I just thought it was baby fat until Dr. New took one look at him and new immediately that he was on way too much cortef.
I think you should ask your doctor and of course get his levels checked often.
Sandra