How should I clean the infected piercing? With what?
Wash your piercing with regular soap and water, then put peroxide, saline, or salt water, never use alcohol it may kill stuff but it will irritate it very badly, happened to me. Do this every day or what my BOCES school nurse did for me because even though my piercing have been pierced for years I guage them so the hurt once in a while, she told me to wash my piercing and put neosporin or a triple antibiotic ointment on it, it won't hurt your earrings if you have good stainless steel and it won't sting a bit, but it does create quite a bit of a mess.
Go and speak to your piercer. And do not put anything other than saline and sea salt on your piercing until you do talk to your piercer.
try and alcohol wipe, alcohol, or peroxide, it will sting but well help clean it up