Has red pus filled bumps from his waist down very hot to the touch and is complaining of pain?

See MD. Difficult to diagnose a rash without seeing it. Could be a skin infection or insect bites. He needs to see his physician for a proper diagnosis.
See doc ASAP. See pediatrician in after hours clinic, urgent care, or call on call pediatric service. If he has fever greater than 102 degrees F, in severe pain, lethargic and difficult to wake up, not drinking or urinating, to ER. Sepsis, infectious agent in bloodstream, in a young child can be very serious.