As a former TA for one of the "bad" professors, you can somewhat rescue your rating, but you basically have to be a hero, and the professor needs to not be mali

As a former TA for one of the "bad" professors, you can somewhat rescue your rating, but you basically have to be a hero, and the professor needs to not be malicious (if the prof wants to fail everyone, not a lot you can do). You have to attend every lecture (I did anyway), redirect / fix during discussion / lab, help them learn what they need to know to pass the exams, and if you have time, what they should remember when the term is over for their future academic / work careers. Only bad ratings I recall were from students who only attended the last discussion section; it's hard to teach 10 weeks of theoretical CS in 50 minutes.