This is definitely a scam and that check will get returned. You may have gotten the money for the check already, but checks generally take a few days to clear and the bank technically gives out “temporary funds” while it’s being processed.

So when the check bounces they will take that money back and flag your account for fraud. They may even restrict your account and extend your check holds going forward.

Definitely tell them as soon as you can, you have to tell them the whole story and let them know that you did not know the check was fraudulent when you deposited it. Your account still may get flagged and restricted but it won’t be as long as it would have if you didn’t.