Alpha Erased by Aileen Erin

Tessa—part witch, part werewolf, raised human and now the unofficial leader of a newly minted supernatural alliance—thinks nothing of her brother, Axel, texting her and Dastien to meet him. The location pin was in a weird spot, but maybe he’d found a magical anomaly there. But when Tessa steps into the darkened warehouse, she doesn’t expect to see her brother laying in a pool of his own blood, smell the sulfuric scent of black magic, or feel the pain of her mate being shot full of silver.

Tessa has seconds to make a choice, but there’s only one thing she can do to save the two most important men in her life—sacrifice herself.
The last thing Dastien hears from Tessa was her plea—help Axel. But then their bond goes silent. He can’t hear her. He can’t feel her. And there’s no sign of the attackers who took her.
Dastien does everything he can to save Axel before calling his friends in a panic. It takes all of them to find Tessa, but when Dastien’s finally reunited with her, there’s no sign of recognition in her eyes.

No magic in her touch.
No wolf beneath the surface.
Everything that made Tessa who she was…has been erased.