Hello dear your puss discharge behi f the ear inspite of taking medicine is something to concern,,,,let me describe things,,,,the bump behind ear is either infection in
lymph node or in mastoid ,,,,mastoid is considered part of
inner ear ,,,,mmastoiditis if left untreated ca leave hearing problems,,,,,
consult ent specialist ,,,,stop antibiotics for 48 hours theh do culture and sensitivity of puss and tAke antibiotics accordingly,,,,take care stay blessed