If you are similar to me you probably already spent ungodly amount of hours researching everything on net, trying to find some cure, trying to find any way to get rid of it. That way you focused on T even more. Ie were throwing your habituation progress out of the window.
You need to stop fighting it. Few tips - you probably are constantly checking your T by inputing fingers in your ears to hear it properly. Cut it. Stop it. Do not do it anymore. Just prohibit yourself from ever doing it. No good will come from it, nothing that can help you. Try magnesium, it helps with muscle tensions and eases tension inside you. 8 hours sleep. Every day, period. Dont care how difficult it is, dont go to sleep at 4 am when you are waking up at 7.
And this is tip that 70 yo doctor gave me. Your brain isnt used to this sound. It perceives it as a threat and that triggers gajillion of processes inside your body, making it all worse. Spiking anxiety, triggering flight-or-fight effect and all that jazz. You need to rewire your brain so it wouldnt perceive it as a threat. Nature sounds are good in this. Experiment with sounds, you have app at mobile phone called White Sound with many different sounds and ability to download even further on. Find some that soothes you. For many its sound of water, but whatever works for you, and have it on when you go to sleep, but at a volume that is below your T. You dont want to mask it, you want to create association in your brain with sound that relaxes you. At the end of the day, however, what it mostly takes is simply time.