Middle Ear Infection or External?

Hi I have just been to the doctor for an ear infection, i think i got it from blowing my nose to hard after using a neti pot.
She prescribed me with an antibiotic to put in my ear ‘neomycin and polymyxin’ however it doesn’t seem to be doing anything.
My ear is still blocked and ringing – i’m wondering if it’s an Middle ear infection and am paranoid about it as i’m a singer and have heard horror stories about brain issues…. I have no fever but have a sore throat and sinus issues… what can i do here?
It’s been 4 days and the ringing is driving me CRAZY!
Does it sound external?
should i keep using the drops – it’s been 3 days.
Thank you!!!