Esperanza:
Just to clarify. The "onset of pain" I was referring to in my prior reply is only temporary -- that is, the pain only lasts until the sound level is lowered below 120 dB or removed. It is theoretically possible, however, that your increase in tinnitus is due to additional damage caused by 120 dB of sound level being piped directly into your ear. Who knows?
As for your audiogram having been taken at a major hospital, this is no guarantee that it was accurate. One of my dubious audiograms was taken at a highly respected medical facility, yet their equipment was substandard. The cabling that led to my headphones was microphonic; that is, it picked up the sound of my breathing very loudly. Therefore, the sound of my breathing masked the lower-level tones such that I couldn't hear them, leading to unrealistically poor results being recorded. At another facility, noise from the HVAC system outside the supposedly soundproof testing booth was louder than the lower-level tones, again compromising results.
The booth and equipment at Stanford, on the other hand, were virtually dead quiet. If I couldn't hear a tone, it was because my hearing ability at that level and frequency was shot and not because my breathing or the building's air conditioning/heating was drowning out the tones I was trying to hear.
The bottom line: if it's not absolutely dead quiet in the testing booth, then you and the audiologist have no idea at what threshold you can hear different frequencies. Shop around.
Best wishes,
Tumbleweed