Lydia seems to have become invulnerable
Target Lydia in the console, then use getav x where x is an actor value indice like health or CombatHealthRegenMult. Try using resurrect on her, it should reset her stats to what is appropriate.
Target Lydia in the console, then use getav x where x is an actor value indice like health or CombatHealthRegenMult. Try using resurrect on her, it should reset her stats to what is appropriate.