Can a lawyer change a contingency fee after the case is settled?

I'm assuming that's $50,000 each, but it's still not fair.  You have a fee agreement, which I'm assuming is in writing (most courts require that, for contingency fees).  There might be some good reasons, based on the work put into the case, for your lawyer to ask for more, but that should have been brought up with you and the other class member before you agreed to settle this case.

Your lawyer might be able to ask the court to approve the higher fee, because it is a class action;  if that happens, you need to hire another attorney to resist this, because $67,000 (between the two of you) is too much money to walk away from.