What substances most quickly repair/regenerate nerve damage in cat's tail?

Five or six days ago the cat experienced nerve damage near where the tail joins the back. It may have gotten its tail caught in a door, stepped on, or some nasty person may have kicked it. This kind of injury conventionally takes up to three months to heal if it heals. Thiamine - vitamin B1 - is recommended to help heal. I will apply DMSO near where the tail joins the back daily. Now I need to know what will most quickly repair the nerve damage: DMSO, comfrey salve, hypericum perforatum, arnica montana oil, methylene blue? I need to research this.