No there is not an injection to cancel the depo injection you have o wait out the whole 12 weeks.After the injection wheres off it may take up to 12 months even loger for your menstrual cycle to come...
Neurologists use dexamethasone for many diseases. To shrink swollen brain due to tumor, to treat meningitis, to treat some kind of peripheral nerve disorders, etc. One may refer to neurology websites...