No, about the "water in the mouse would help re-hydrate the snake"... it's really better to avoid feeding a snake that's shedding; many snakes instinctively refuse to eat, but even though a young snake is hungry & wants to eat, they do better doing "one thing at a time". It's not the end of the world though & you'll know better next time.
If in doubt (about feeding & the state of their hydration) wait it out...Feeding larger prey would just be THAT much HARDER.
You can't believe everything you read online. A poorly hydrated snake that's fed larger prey is even MORE likely to regurgitate it...their body won't be able to handle it.
FYI, anyone taking in a "rescue snake" (in poor under-fed condition): hydration is always the first thing, only after that is addressed comes food. Without hydration, snakes cannot digest properly, & since regurgitation (especially of larger prey) can even KILL a snake, you want to preclude that from happening.
Your heart's in the right place, just need more experience & knowing who & what to believe online. Don't beat yourself up, we've all blown it at times. Myself & others here have been keeping snakes since before there were forums to ask.![]()