If this sunken dorsum (aka saddle nose deformity) did not happen all of a sudden from the very first look after cast removal... means it is not an over resection (or not totally) but instead a progressive procedure of landslide or collaps due to support; I understand, therefore, the cause of your sunken dorsum lies at the septum... well, or at its absence... you likely received a total removal of septum instead a septoplasty (a septoplasty is a modification or realignment of the septum, admitting partial frame removals, but never a total removal of the caudal septum which is sadly common).Once the caudal septum has been removed the supratip and the tip lack support and do collapse, however not the nasal bones which stay firm as they are bony. However, if the alar cartilages are strong, the nasal tip skin is hard and holds shape memory, then the tip may not collapse or collapse minimally, so... what's left collapsed then? the supratip area and the middle vault (upper lateral cartilages). These noses have a very typical and easily detected look, either the lower 2/3 collapse or the middle third only.You may belong to the latter, the group of middle vault collapse and sunken supratip, with minimal (if any) tip collapse.The treatmend will depend on the real and well diagnosed (by expert hands) lack of support, tissues properties and aesthetic goals; in some cases it is enough to graft the sunken dorsum.If the removal of septum took place recently the collapse may be restored, but this rarely happens, they are normally septoplasties received long ago and therefore un-expandable.Sometimes the tip needs additional support, like a strut graft.Beware of wrong diagnosis or weird surgical proposals, firstly you have to be well assessed visually by an expert in revisions.If you wish better grounded opinion please do post or send privately well lit, focused and standard images: frontal, both lateral and both oblique views, also underneath the nostrils. Feel free to request any additional information from me.