If you havent dealt with a shed yet (or with many, as some go differently than others) then theres a good chance it hasnt shed yet. Most of the snakes ive seen shed went pretty clear and looked good about a day before they actually shed. Also, if its a very small snake and it had quite abit of water to be in, then the shed may be rolled up in a little ball (our baby rat snakes did that on their first shed) and it would be easily over looked. Also, as joe said, it may be in the substrate, if you're using some type of mulch or shaving type beding.