I wanted to write in as I just experienced the same side effects from a tube that was put in my ear. I experienced hollowness, like I was talking in a cave or in an indoor swimmming pool area immediately after the procedure and it continues for a good two weeks. Today I couldn't take it anymore so I demanded to see my ENT, he checked it over and upon initial examination it seemed fine. He then looked with a microscope and discovered it was 1mm to shallow or off center and he corrected it. I immediately felt relief and could talk without sounding like I was in a tunnel. Regardless, I made the doctor remove the tube altogether as I couldn't chance it, it was literally driving me crazy. The tube has been removed for a few hours, I still feel hollowness when I speak, but I hope it's just from the trauma of the procedure.
Hello and hope you are doing well.
Once the post op inflammation subsides, the hearing should be normal. The headache could also be related to the procedure. You can use OTC Acetaminophen for relief from pain. However, if your symptoms are worsening consult your doctor to rule out an infection.
Hope this helped and do keep us posted.