Why The Veins Of Foreskin Is Having Burning Feeling?

My 11-year-old son is not circumcised. His foreskin has yet to fully retract. He hasn't had any physical issues or pain until today. He is complaining of burning in the veins of the foreskin. It hurts more when he attempts to slightly pull the skin back. I noticed a white residue around the rim of his penis. What is happening? Does he have an infection? What ointment can we put to help reduce the pain? And even more, get rid of the problem?