See the previous thread on Tinitus to see info on hearing standards.
Appreciate your anxiety on the career issues but don't worry, so long as you can get through the medical now, when established as aircrew, being grounded from hearing loss is very rare.
Most of us do have high frequency damage! Re-certification standards are not very strict. And even if you fail on the limits all that is needed is a check in a simulator with a trainer to say that you are ok to carry out your job.