I'm a senior and I'm taking an AP Biology Cl and I have a question about fairness.?

When taking the cl, one student complained to the teacher after a more difficult test and was given the opportunity by the teacher to retake the graded multiple choice section, re-guessing the answers she got wrong for full credit. Not only did the teacher not present the opportunity to the rest of the cl but she also hid it from everyone. The student, who believes it was fair to be able to retake it because she asked the teacher for help, told a couple students about the situation. Her fifty-something grade on the test turned into a ninty-something after the second chance while other kids with 70s and 80s weren't given a chance to improve to that level. When we confronted our teacher she promised it was a one time deal but recently, about a month later, gave the same student another identical opportunity on a test we alll failed. The teacher has given different parents completely different stories and the student believes because not everyone is born with the same abilities, some students need extra chances while others don't. Am I completely out of line being upset or would it be appropriate to approach administration at this point?