Well, I've had PCS for six months, and this is the first time I've experienced this (my symptoms, tinnitus included, have been gradually improving otherwise and I've been feeling better over time).

I strongly suspect that what I'm experiencing is linked to my putting in earplugs shortly after taking a bath, and keeping them in for half the night. I think I've experienced something similar a couple of times prior to my injury. Could it be an ear infection like swimmer's ear? I guess I'll have to go to my family doctor to find out.