[cypher]

Sorry to hear your girl hasn't been well, it doesn't sound like the common onset symptoms of Cushing's so I doubt you need to worry about that.
It may just be that her eye will need a further course of meds to clear up, sometimes infections can take a while.
The discharge from her eye is most likely porphyrin which is fairly common with eye problems.
Is it possible she's been rubbing the area under her chin on anything? It does sound like an odd place to have hair loss & doesn't sound like mites (which are not really anything to do with her cleanliness btw).
I wouldn't use teatree for a hamster myself, if you want to put something on it to soothe it & possibly help heal it you could try a drop of evening primrose oil, taken internally this can help with skin problems so it won't hurt her to ingest it after grooming.
Good luck at the vet, hope they can get her better for you.