OH NOES! The Death Mark of 16! What could the MC possibly do?
I mean, other than if he can change a skill level from C to B, it should be trivially easy to change the Death Mark of 16 to the Death Mark of 916, dooming her to die when she turns 916 years old.
But it couldn't possibly be that simple! Could it? COULD IT?!?!
(Yeah, I'm guessing it is exactly that simple, but we are going to have to fight through social status nonsense again.)