Because it is dark, painful, and looks swollen, it should be taken seriously, especially in a child. It could also be irritation from an insect bite or, in some cases, an infection. If the pain is strong or the child cannot walk normally, it is best to have a doctor check it.
Do not pop or cut it at home. Opening it can increase the risk of infection and make the swelling worse. Keep the foot clean, avoid pressure on the area, and let the child rest with the foot raised.
For pain and swelling, a cold compress wrapped in a cloth can be used for short periods. You can also ask a pharmacist or doctor about a child-safe pain medicine. Seek medical help quickly if redness spreads, warmth increases, pus appears, fever starts, or the pain gets worse.