I understand your concerns. I am about to graduate as an RN on Dec 17th. I do know its hard work and when YOU have prepared efficiently for an exam and the ones who did not, are getting scores equivalent to yours, or higher, can be very disappointing.
If I were in your shoes, I would suggest a cover sheet for exams which is what our instructors passed around first (just a blank sheet of typing paper). We folded it down the center and put our scantrons in it and slid our coversheet down as we proceeded further dow the scantron.
I would notify your professor and maybe he could have another proctor in the room as well. My microbiology class was in a classroom setting exactly like the one you are mentioning so I know how easy that is to cheat.