Tinnitus is caused by cochlear synaptopathy.
For example, if you go to a club without earplugs, the loud music can damage cochlear synapses, destroying many of them. As a result, your hair cells still pick up sound, but there are far fewer synapses to receive and process the sound information. It is like a damaged microphone that cannot pick up sound properly.
To compensate for the loss of sound clarity and reduced signal input, your central nervous system increases central gain in an attempt to restore normal hearing levels. However, in the process of turning up central gain, tinnitus develops—just like how turning up the gain too high on a sound system to compensate for a poor-quality microphone would create buzzing and ringing. This also leads to a loss of sound clarity and fidelity.
If Cilcare's drug worked, it would restore sound input, allowing central gain to return to normal levels. As a result, hearing would improve with better clarity and fidelity, and the ringing would go away. That is why targeting cochlear synaptopathy could potentially fix tinnitus.
No, it could not make everything worse. If the synapses were regenerated, it could only lead to improvement—better sound fidelity and clarity, increased sound input, and less or no tinnitus and hyperacusis.