Re: SOS NIKKAH SARI ADVICE PLEASEEE
A lot of karigars will cover the kaam on the back with a jamavar pati both as a design detail and to hide the threads. That may not be an option for you if you can't get your hands on matching fabric.
Depending on what you are trying to accomplish - if you want to merely tidy the threads, some karigars added tulle netting to the back of kaam and that keeps it from pulling/fraying. If you want to hide it altogether so it is not visible, you may want to add opaque fabric. That being said - the fabric shouldn't be too heavy or it will affect the weight/flow of your saree fabric.