Botox cheek droop. Is it permanent?

I had bad botox result on crows feet 3 months and 1 week ago. A second opinion confirmed my zygomaticus muscle on one side had been weakened from migration. My cheek still feels heavy and lip is still curling under. Cheek looks flatter than other side. I expected to see some improvement by now, could this have a permanent impact? Or could it last as long as botox seems to last for other lower muscles like masseter muscle? Very depressed over this but need to know exactly what I am dealing with.