I have some kind of a Flea on my back and shoulders, I dig them out with my finger nails, and two hours later they are back, I've tried Kwellada-P Lotion, vinegar, NIX dermal cream, nothing will kill them . they are eating rite down in my flesh, I just soaked in HOT water for an hour trying to drowned them, that didn't work, what can I do to get rid of them.