My nine year old son has a wart looking thing on his knee but i can not see any black dots, he peels it off but it's still there?

Warts: Warts can be very stubborn to treat, particularly with over-the-counter products. They are caused by a virus. If the treatment you are using doesn't kill this virus, the wart persists. I would recommend that your son be seen by a dermatologist. He/she can determine if the wart is still an issue and treat it in the office if needed.

Common: Part of the mass and all of the warts root system extends blow the skin surface. Effective wart removal will always create a divot in the skin (wound) to get all these elements or it will regrow. If you have tried all the OTC methods and the kid is still complaining, see a doc with the proper tools to remove it for good.