for very young dragons, as your sounds like ,if he is only the size of your thumb (length wise, I hope, not thickness), you do need to find somebody reliable to come in 2-3 times a day and feed him. If you have small silkworms, you can leave them safely in the cage (on the cool side of the cage) in a low container that is high enough the silks can't easily climb out and low enough for your dragon to get into it to eat. The silks can be left in there with a few days worth of silkworm chow. They won't hurt your dragon while he sleeps and he can snack on them whenever he's hungry. However, as the chow does dry out, this is only really good for a day or two, deffinitely no longer than that.
the only real alternative is not to go anyway till your dragon is 8 months old or older, where they can go a day or two without eating, without having any risk to their health.
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PHLdyPayne