Daily reminder that Pokémon are tools and tools do not deserve sympathy or pity. A tool's usefulness extends as far as it is able to perform its assigned task; if a Pokémon is permanently injured in a battle, its worth as a tool has ended and it should be discarded.

Mega Evolution hurts a Pokémon? So what. Mega Evolution creates a better tool, if only temporarily. Use it liberally, and if your tool breaks... replace it. Simple.