Wait its mean that eri chan already know how to control her quirk??

No it means that they found a antidote for eris quirk bullets

Aaahhh is that so

Chisaki had both the bullets, one to take and one to restore. The blue bullet restored.
They did give twice some of the bullets so try and replicate them and Hawks was undercover for while.
They also had all of chisakis research.
Its possible they either stole or replicated the restore bullets.