Snape did attempt to redeem himself for his actions, in the name of his love for Lily and guilt over her death. The impact from his sacrifice was massive in the way it led to the fall of Voldemort. Snape's demonstrated ability to love also sets him apart from Voldemort.

Did Snape really redeem himself?

And then he had to kill the only other person who knew whose side he was truly on. And ultimately he died because of all that. So yes, I personally think he redeemed himself. People change, and even though Snape was still a jerk, I'd say he did way more than most people would be willing to do in his situation.

Is Snape redeemed?

Snape was redeemed by Harry Potter. If Voldemort had murdered the one-year-old along with his parents, Snape would have no reason to live. He would have died a traitor and a coward. Yet because Harry Potter was The Boy Who Lived, Severus Snape became The Death-Eater Who Loved.