Mites could make a snake go off feed but so could a number of other things.

Husbandry off
Prey not warm enough
Prey not the preferred kind (live, prekilled, f/t, mice, rat)
Coming shed
Just being a snake

That's to name some common things.

With more info on your snakes feeding history we might be able to offer more help. As for the mite possibility I would put the snake on paper towels instead of newspaper. The white paper towels make it easy to see mites. They will look like little black specks. Also your snake suddenly soaking may be a sign of mites.