Without the benefit of pictures or an examination, it is very difficult to give you sound advice. Rib cartilage might warp but is doesn't usually break. I am not sure what is causing the gap but it would be nice to see a picture.
Consult your surgeon.
The use of costal cartilage to reconstruct a nose requires a longer healing period. I would be patient and reassess the result with your surgeon.
Without a photo it is difficult to discern what you mean by a gap, but it's likely too early for a rib graft to warp. It's possible you might be feeling the edge or end of the graft. Be patient, waiting at least 6 months, to determine a final outcome.