I agree with Bogertophis. It sounds like he’s going into shed. I’d leave him alone and just watch him for the next week or two. You can feed him again after his shed. I wouldn’t be concerned with his weight at all. I don’t weigh any of my snakes. As long as his temps and humidity are good, and he’s got fresh food and water, along with a couple of hides he should be just fine. I know it’s natural for any new “snarent” to worry about their young ones, but they really are very easy animals to keep once they’re set up properly. Sit back, relax, and enjoy your new critter!