I have a ruptured disc and resultant facet joint pain. Every 9 months or so I go to my pain management doc to get an RF ablation done. A little wire is threaded down through a needle to deliver RF waves to the nerves to effectively fry them since they are only pain receptors. So RF does have a verified use in destroying nervous system tissue. Now that's really up close, who knows what smaller doses over the airwaves would do but I suppose taken cumulatively over time there could be some effects.
I still contend that the skin acts as a "Faraday cage" that prevents radiated mm-range frequencies from penetrating deeper tissue.