In case you haven’t come across this thread yet already, it’s discussed here:
Rimegepant for Treatment of Migraine and Phonophobia (Hyperacusis?)
Looks like someone has tried it for loudness hyperacusis, but it had no effect.
Looks like she is the guest of honour at an upcoming tinnitus & hyperacusis conference. Hopefully she provides an update on her research.
Management of the Tinnitus and Hyperacusis Patient: 30th Annual Conference