Pus and irritation each time the earring goes in can come from a reaction to the earring metal, an infection in the piercing, or both. The helix is cartilage, so it heals slowly and can take many months. When the earring is out, the healing skin closes quickly, which is why the hole shuts so fast.
Next Steps
Clean the area gently with saline or mild soap and water, then pat it dry. Avoid touching, twisting or sleeping on that ear. Try not to keep taking the earring out and putting it back, as that reopens the wound. See a dermatologist or your doctor to decide whether to keep it in, especially if the pus keeps returning.
Health Tips
Get seen urgently if redness spreads across your ear, a painful swelling forms, or you develop a fever.