The archwire bending between the last two brackets is the first step before it comes out completely. If this happens, you'll see the wire sticking out slightly and moving when you eat and talk. It may injure the lining of your mouth. Wax doesn't stay on an archwire for long, so it isn't a good way to deal with the problem. If you have a small pair of tweezers, you can grip the end of the wire and guide it back into the opening of the last bracket. If you can't, you can of course book an extra appointment with your orthodontist.
This answer is for general information. Your own case needs an examination by an orthodontist.