How long do the symptoms of vitamin b6 toxicity last?

Depends: Vitamin b6, when taken usual therapeutic dose, is not toxic. It can cause significant adverse effects, however, if you take too much of it for a prolonged period. Depending upon the amount of vitamin B6 ingestion, toxicity ranges from nausea to dependence or permanent peripheral neuropathy.

Some may fade....: When there is tingling, that may fade with time once poisoning with B6 stops. However, because B6 is toxic to the sensory ganglia and causes permanent cell loss there, the loss of balance tends to at least partly remain even after the poisoning stops.