My hearing is fine at least according to the medical tests made at the end of my active service.
When you get tinnitus like you described, it is because some cells are damaged. They will continue to send a constant signal to ones brain. When it stops, it is not caused by the cells healing but because your brain simply starts ignoring those cells. So this would manifest itself as an inability to hear high frequencies. Here's a test if you're interested: http://www.youtube.com/watch?v=4G60hM1W_mk (high frequencies are from 4:30 onwards). It is hard to say exactly what is the normal result, as it differs with age an such. But I could only hear up to 13kHz, so my hearing is definitely somewhat damaged
EDIT: @dIZZyBlIZZy: An improvement? Did they measure decibels or frequencies? I was under the impression that damage to ones hearing does not heal by itself but I'm no expert.
EDIT2: To give people some guidance, for people under 25 years old, the normal range is somewhere from 20Hz to 20000Hz. For over people over 25 years old, somewhere around 20-15000Hz would be normal. But these things vary, and that's just some rough guidance for people taking the test