What Causes Pus Discharge At The Site Of Piercing?

I have a gauged ear and recently stretched from a standard 1mm earring (normal everyday size) to a 2mm using a surgical steel taper. I now have what appears to be a boil next to the piercing, with a cotton wool bud I can press and puss comes out, the boil looks smaller then fills with lymph. Please explain what is happening? I was using Savlon wound spray to keep it clean twice daily, then a little Vitamin E oil (I worry this could have been a problem) now surgical spirit due to my recent concerns. Thank you for your advice. x