How Can The Swelling And Lump In The Ear Be Treated?

my daughter had her ears pierced in July, we kept them clean etc and everything was fine until her friend accidently caught one earing during a cuddle. she has since had a swollen lump inside which was leaking puss for a few days but the puss has stopped but still has swollen lump. i am unsure how to reduce the swelling without causing further discomfort.