I ended up with the marked for death glitch on Shadowmere, giving her negative armor, so I've decided to kill her and spawn her in using console commands. I know I can wait several days for her to respawn, and I hear there's a mod that removes the glitch, but I want to spend as little time as possible on this. I will be making a save beforehand anyway, but I would rather not risk making more progress only to find I've broken my game. I have hearthfire, but not dawnguard or dragonborn.
Note: feel free to edit this wall of text to make it easier to read, I'm terrible at writing.
TL;DR: Will spawning shadowmere with console commands cause difficulty later in the game?