You'll have to remove the ticks with some sort of tweezer device (or your fingers if you choose). Place a towel or something comparable over the head of the snake if it's aggressive. This should calm it down while you remove the ticks.
I would keep a close eye on the animal(s) because ticks live in various stages. Just because you don't see them doesn't mean they're gone. There could be eggs that will hatch soon and they'll be visible as tiny ticks. Feel the skin well for "lumps" as these are commonly ticks under scales.
Provent-a-mite is a great product but use as indicated. If you spray the animal down with it, make sure there's VERY GOOD ventilation in the cage before placing the animal in the cage.
Good luck to you and if you keep at it, you will most certainly eradicate the ticks.
Ron Crawford