Nope, the penalty of not finishing the test is higher than wrong answers. Try to make educated guesses. If there's no time for that either than just randomly guess, but its very important finish it.

Definitely, guess and do not leave it blank! It might be helpful to practice pacing now, so you can finish the test (and go into the test with the confidence that you know you will finish!). Spend less time on the ones you don't know throughout the test, so you have time at the end. Know what you know and know what you don't know, so if you see a question that you don't know, you can guess and move on. Also, pace yourself as you are taking the test, so you can better manage your time. For example, know that by 30 minutes remaining, you should be on question #?. I made a chart that helps me and I write it on my notes when I take the test, so I can be more aware of pacing issues and can adjust while taking the test. I hope these tips help, even just a bit!