When your kid sustains wounds, his body launches a three-phase process of healing. The inflammatory phase, which is his body's defense against injury, occurs immediately and can last three to four days. Some of the signs include redness, elevated temperature, swelling, and pain, so while these are technically causes for concern, understand that this means your child is also on his way to healing.
Clots form as a plug to stop the bleeding and provide initial wound closure so bacteria and viruses will not enter the skin. However, as this happens, there's a chance harmful bacteria like Staphylococcus aureus or Staphy can still enter, get trapped inside the clot, and cause infection.
As the wound continues to heal, a scab may appear, which protects the new skin cells being formed. Your curious kid will find it difficult not to touch and tinker with that itchy scab. Keep him from scratching it off so as not to interfere with the normal healing processes nor induce scar formation.