Now my mouse has a head tilt

In my previous post, I described how my mouse, Schtunkie, had mites, then yeast. He no longer has mites or yeast and his fur is growing in, but now he has a head tilt. He runs around in circles and stays in the bottom of the cage, doesn't use his tubes anymore. The vet prescribed liquid Baytril and I give it to him with a tiny syringe, directly into his mouth. He has been getting daily for three days now but I don't see improvement. I'm supposed to give it for 14 days. Has anyone had a mouse with a head tilt that got better? He was a healthy mouse until January of this year, then these problems started. He will be 2 yrs. old in April. Is this what happens when fancy mice reach this age? Any information, help, or shared experience would be deeply appreciated. I'm afraid I'm going to loose him and he has been such a good pet.