One occasional PR is not going to cut it. "PR" means building a quality narrative and story line, regularly maintained, that shows value to retail investors. Provided via regular and cohesive (professionally written) press releases that build on each previous release and create a good story.
Pub Company Marketing 101 - A company has to market itself as worthy of retail investor money and maintain that trust.
Occasional sporadic PR does little beyond a light pop, and if done incorrectly causes a drop in price (as we have seen).