NO.
You will not get any negative mark for selecting a wrong answer in your PMP Certification Exam. Therefore, never leave any question unattended even though you don’t know the correct answer. Select your best guess. Leaving a question will not give you any mark; however, if you answer any question for which you don’t know the answer, you at least have a 25% chance that you will be correct as out of four, one is surely the right answer.
Therefore, answer all questions in your PMP Certification exam even if you are not sure about the answers to some of the questions.