Very small white pimple like bump on vulva. not painful or itchy. havent been sexually active in a year. could this be vulvar cancer ?

Not likely: This might be an inflammed Bartholin's gland or a minor skin infection. Would apply warm compresses & hopefully it will resolve. Contact your doctor if the area become significantly red, inflammed, tender & warm.

Please see your Gynecologist for a thorough examination and recommendations for treatment. If you don't have confidence in your Doctor please see another for a second opinion.

From your description it does not seem to be cancer but see your MD or Gyn for it could be a boil, a lipoma or a cyst or something similar.