What I would suggest you do is rally the troops. Don't make this about your concern: you don't want the story to be "I'm worried.", you want the story to be "The choreographer has been complaining about the dancing being thrown off by this hazard, the costumes people are concerned that someone might take a nasty trip and end up damaging their outfit, the dance captain reports that several dancers are so nervous about this part of the stage that they actively avoid transiting through it, which throws everyone else off, and the class rep has spoken to me about the same thing. This is a serious problem which is affecting many aspects of the show, and we need to deal with it."
The stage manager is ultimately responsible for the safety of everyone on the stage, but you'll probably get more oomph if you have some other people on your side. All you have to do is walk up to them and casually mention something like "hey, do you see that divot on the stage?", then make note of their response. ("Oh yeah! A chorus member took a nasty spill there last week, I've been meaning to talk to you about that...")