Benzocaine Powder in Sinus Rinse to Help with Blunt Force Head Trauma Induced Tinnitus?

First let me say I understand this idea is highly risky. Benzocaine can cause a potentially fatal blood condition called Methemoglobinemia.

I'm curious about the possible beneficial effects of mixing some Benzocaine powder with a Neti rinse or putting some on above teeth behind upper lip. I say this because my loud tinnitus was caused by blunt force trauma, which opened a scalp wound, broke my ear drum, and caused Eustachian tube damage, as well as nerve damage. I can press on my upper lip and sinus area and it changes the pitch and volume of my tinnitus (they are constantly changing anyway on several frequencies at once) but touch of these areas cause noticeable immediate difference. Also pins and needles, headaches, twitches are common around my left ear and just above on my scalp which took the trauma. Three and a half years have gone by but nerves haven't settled down and tinnitus is as loud as ever. I'm guessing there is some nerve damage, and by using Benzocaine, I might be able to dull the tinnitus a little, and figure out more about other treatments that might help. Obviously Methemoglobinemia is a very real concern.

Has anyone had any success with blunt force head trauma induced tinnitus and using products such as Lidocaine or Benzocaine?