MythBusters notwithstanding I have an RF burn on one of my fingers that was barely visible at the surface when it happened but which totally cooked the tissue up to about 6 millimeters inwards. It's a pretty weird spot, 2.5 mm across and even 35 years later it hasn't healed, the zone is simply dead to the touch even though the flesh has recovered. You can also still see exactly the shape of the original burn.

Note to self: pay attention when trimming HF transmitters about where you keep stray digits and where the locations of the tops of trimmers are relative to those digits.