Hi -- I, too, would advise talking to the instructor. When I assign a group project, I let the members of the group grade each other, on a very brief instruction sheet that asks several questions about why the grade is being giving (such as: How do you rate this person on how much he or she contributed to the completed project?). The average of the group grade counts toward each person's grade for the project.

If your instructor does not have a process in place for this balancing adjustment, you definitely must speak up.