Dont use cotton buds, clean them up with a baby wipe but dont prod around inside her ears as their realy delicate an you could do some damage.
If its ear ear infection then they will probs give antibiotics and ear drops. Ear mites will need stronghold to treat them.
If you say its her cheek though have you checked her teeth aswell. Could have a bad tooth or something, is she eating and drinking ok.
Realy she needs to see a vet as they will know, you probs will spend more trying different petshop things instead of just getting it sorted
streight away with stronger stuff from the vets.