They can get mites from many places. Did you get him from a pet store? Have you visited any place that their reptiles had mites, like a petstore. If you held one that had mites, then held yours, he could get them. I have never used prevent a mite before, but have heard it works wonders. Make sure you read the instructions fully before using, becasue it is pretty strong. If not used correctly it could harm your little one. Hope this helps.