How to heal SP in final palace?

Im in Maruki's palace, at what im assuming is his final boss fight, where you have to destroy the tentacles and his persona before dealing damage to him, and im severely underleveled, im now at lvl 88 after grinding for a bit inside the palace but now im entirely out of SP and Lorenza wont heal me at the "Laboratory Entranceway" and I dont see her again until the final boss. How the hell can I heal SP? Even if I wanted to just fight him i wouldn't be able to do anything. I have no saferoom items either.