Hello, I'm Dr. Deb.
I recently came online and see that your question about shelly hasn't been answered. I'm so sorry that you've had to wait for a response, but if you still need assistance, I'd like to help if I can.
There are a fairly limited number of possible explanations for these symptoms you're seeing which I'll list below.
A head tilt indicates vestibular disease although the underlying cause may not be immediately obvious.
1. An inner ear or middle ear infection which could have developed as an extension of her previous outer ear infection or could have developed on it's own.
This is going to be the most common cause for a head tilt in a dog this age although it would take an MRI to definitely diagnose such a problem (not something most of my clients can afford)Most patients will respond quite well once antibiotics are started.
lesion such as a tumor or encephalitis...although I'd expect her to have other neurologic signs (and she's on the young side for a brain mass).
3. Hypothyroid disease can predispose some dogs to have issues with an inner ear issue but it's not as common as an infection (#1).
If this were my case, I'd start Shelly on antibiotics and expect to see improvement within a relatively short period of time (< 7 days). If not, then additional testing may be required.
I hope this helps although, again, my apologies for the delayed reply. Deb