Keep offering food and check your temps. Also, if you have the 2 of them housed together, separate them into separate enclosures. I would keep the small crestie in a small enclosure. It will be easier to monitor and have an easier time catching/finding food.
I had something similar happen last year to a hatchling. It was the smallest of 4 hatchlings in a 5 gallon. She was the least enthusiastic when it was feeding time and it began to show. I separated her out into her own cozy little medium sized critter carrier and within a week, she was conquering crickets and queen of her little domain. I really do think the others who were a little bigger intimidated her. I never witnessed any bullying but thats not to say that it didn't happen.
Keep me posted.

Severa