what you can use is bedding spray like the one for lice(almost the same bug) spray down the bedding that you will be useing. let it dry for about two hours and do it in a paper bag. then change the bedding for the mice and that way your snake won't get mites and it won't gt possioned either.
it may take more that one treatment. you can also use camp spray that is used for clothes and the tent screrans. i use it once a month in the summer and use it on the bark for the snake and no health problems.
good luck