Most benzodiazpeines like Temazepam will diminish the perception of tinnitus because of it's effect on the GABA receptors in your brain. They relieve your anxiety and/or also reduce the perception of your tinnitus volume.
However, it is a band aid solution because long term use of the drug will mess with the brains ability to naturally regulate GABA receptors in the brain, and this is what leads to dependency and subsequent withdrawal effects. The withdrawal effects from benzodiazepines are no joke, and they can lead to serious long term problems. I won't do it any justice trying to summarize it here, but I would suggest you research into it and educate yourself on the possible long term effects of using benzodiazepines like Temazepam.
It's very important to use them only when you really need to, and at the lowest effective dose. It's too easy to slip into a cycle of dependency and abuse - this is coming from someone who has had years of experience with hypnotic drugs (benzodiazepines and z-drugs).
I would really advise against using a benzodiazpine like Temazepam during the day because it is specifically designed for it's hypnotic effects. You might feel normal but it's very easy to black out or end up doing something really stupid without realizing it.
If you're in dire need of some form of anxiety relief during the day, look into something like Diazepam (Valium) or Clonzaepam (Klonopin) instead, their hypnotic effects are less pronounced so it is less likely to lead to any mishaps.