Most probably it is a chronic sinus infection
extending to the ear.
It would have been better if you had mentioned what antibiotic was given and for how long.
Anyway an ear swab may be taken for culture and antibiotic sensitivity test
A longer course of 10 days of appropriate antibiotic after above test may be given if such long course was not given before. In case if culture test does not yield helpful result, Co-amoxyclav antibiotic with a dose of upper limit to her body weight may be given.
B complex syrup may be given to prevent oral ulcers as long course of antibiotic is given
Along with these, using paediatric decongestant nasal drops to nose is important in draining sinuses
off their secretions.
Even after 10 days course of antibiotic if sinus or ear infection
recurs within 2 months then show to an ENT specialist
. May be still longer course of antibiotic under supervision may be required or some other reason for persistence of infection need to be ruled out.