A thorough shower (& all that shaving!) plus a change of clothes (naturally) is likely enough to get rid of any hitchhikers (mites) on you. It "can" happen (human & merchandise transfer) but not too likely.
Personally, I'd avoid buying from a store with mites- they don't always disappear with one treatment, & when you have a new snake, mite treatments will mess up your ability to feed your snake & also it's likelihood to eat for you. It's a very big set-back, having to treat for mites- & they're also blamed for potentially spreading some diseases among snakes- that too is a matter of "luck"- no way I can tell you for sure it's safe or not- only that it's a risk.
It's up to you- if you have other options (local stores to buy from) & what your gut feeling tells you.
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