I first found her hard because of excadrill's shield stuff but then i realized to use substitude.
Here's how the fight went for me:
i led of with feraligatr to brick break the aurora veil and destroy Sandslash
then i let klefki KO feraligatr and then the fun starts
i went into venomoth set up +6 with quiver dance, used sub and full restored
the end xP