@MafiaFox
Well, this what I got from Marvel Wikia about PS
"Penance Stare: Ghost Rider possesses the supernatural ability to cause any individual who stares into his eyes to see and feel every bit of pain they have ever inflicted on anyone in their entire lifetime for all eternity."
-Marvel Wikia
So, as far as I know, PS needs Ghost Rider to have physical contact in order to work. Could be wrong though. But Sans can easily stay away from GR via his reflexes and teleportation (he can also teleport Ghost Rider himself if he wants to).
While Sans isnt inexhaustible like GR, his feat is much better than GR's though. GR's best feat was matching WW Hulk and Dr. Strange saying he was "God-like" at full power, which is very vague on how strong he is, but I doubt he's Skyfather level God-like. Sans' is beating Chara multiple times, someone who can destroy the entire Undertale verse in one hit (while he did get exhausted, Sans only lost because Chara can SAVE and LOAD as much as they want, coming back and learning Sans' attacks. To my knowledge, GR doesn't possess an ability like that.).
Sans is also much smarter, planning and strategizing unlike Ghost Rider who only attacks head on. Also, yes, Sans' attacks damages the SOUL and Body, making it no issue Sans can hurt GR.
So, with better hax, reflexes, and overall smarter, still giving the win to Sans.