Yeah thats crazy small. Sounds like you have him doing 100% better but id have a Fecal done for parasites. My female was a small Hatchling, I got her at 50 grams 2.5 months old and their normally 65-90 grams when born.
She is 3.5 months now and just hit 150G. I fed her every 4 days to get her stats up now going to go every 5 days..
Its hard to say without a Vet visit if you got her with parasites.