Neither of these drugs are actually ototoxic. Benzodiazepine withdrawal can cause vestibular damage, especially if it's handled too quickly or improperly, but if there's actual damage to the hearing apparatus from simple use of benzos no one has ever been able to demonstrate it.
Antihistimines definitely do not cause vestibular damage, but, you're manipulating, minimally, acetylcholine, and additionally many of the older, common antihistamines like Benadryl, are actually not very specific and exert pretty notable serotonin reuptake inhibition (in fact, SSRIs were developed after looking at this mechanism and trying to create drugs which would exert the serotonin action without the antihistamine effect).
Drugs which mess with serotonin function are well known to, on a temporary basis, impact tinnitus perception.
People often use the word "ototoxicity" to relate to "any drug that I think might have caused me a temporary spike". This is just wrong; there are all sorts of drugs that can spike your tinnitus short to mid term without actually doing any damage to the hearing apparatus or the brain.