Were there 4 skeletons total? (2 mages, 2 standard skeletons) Level 5 is a little early to be there, though the room with the statue on the previous level only had one skeleton, that I recall.
If that is the place, the levers you used to get past the 2 doors should allow you to get back. Play with the levers by the northern door, and you should be able to close that one and open the southern one.