What could be the possible consequence if a professor knows about a student's review?

The student needs to establish that the the work submitted is better than the grade received.

1. Understand the grading distribution for the class (should be in syllabus)
2. Collect the assignment/exam requirements, what you submitted and your grade
3. Honestly evaluate what you submitted and see if the grade matches the work
4. Check a classmate's submission and grade to get a sense of what was right or wrong
5. Ask the professor for clarification about the assignment/exam grade (within a week of the assignment grade being given)
6. Check that the final grade is calculated correctly based on the weights in the syllabus
7. If you still feel like you met the requirements, you can contact your student advisor, student support services or the head of the school. Be very clear about your concerns of bias, and offer to have others review your work.

Number 7 is a bit tricky. You should take local culture into account. All of this assumes you are at a university that does have some support systems for students.

Communication is really important. Sometimes the Prof makes a mistake in grading, sometimes the student didn't understand the assignment. Once you rule out both of those, then you could consider a review.