Sounds like a plan to just watch and wait for now. If he's eating and otherwise acting normal, he's probably not suffering. You sound a lot like my daughter who is 14 and really loves her animals. She gets very passionate about them and would do anything to make sure they are happy.
My daughter also has some anxiety issues, and sometimes she fears the worst instead of taking a breath and sitting back and trying to see things from a bigger perspective. She gets this way the most with things she cares about, such as her pets. If her snake doesn't eat on schedule, or her chameleon is not eating as many bugs that day, she gets very very worried. I counsel her to watch and wait. In both cases the animals showed signs of shedding within a couple of days and all was okay.
Her chicken had a weird wheezing noise for a week and I counseled her to watch and wait because it otherwise seemed fine. Turns out the chicken was growing up and its voice was changing from chick noises to adult noises.
I wish the world had more pet owners who cared as much as you do. :-) I still advise trying to find some odd jobs to save up money for future vet bills or other needs though. Also, maybe have some good conversations and engage your mom in your interest of snakes, and show her the research you've done in a friendly manner, so she can see that giving wild mice is not the best idea. Moms get very proud of kids who take time to research and learn things on their own.