Snake mites are species specific however can "hitchhike" on other things like people and I assume a pet if it was in close contact, though I don't expect they could survive long without their host animal. If you are very concerned about this you can always pick up some Equate lice spray from WalMart and give the couch or whatever the snake's been crawling on a good blast. You probably have nothing to worry about that way really. If you have other snakes however you do need to worry about spreading mites to them.

For now while you locate and get some P.A.M., you should thoroughly clean the snake's enclosure, replace it's bedding with layers of plain white papertowels (easiest to see the pesky bugs on). You can bathe your snake in tepid water with a drop or two of dish soap (breaks the surface tension) to get rid of the mites on the snake. This is only a stop gap thing as it does not destroy any eggs so you still need the P.A.M. or you will end up with a reinfestation.

If you have children I'd just keep them from handling the snake until you get this under control and keep the snake quarantined as much as possible. Remember to use the P.A.M. exactly as directed (it does not get sprayed directly on the snake).