It gradually grow, dropping all those unhealthy fur by itself, getting rounder and rounder by itself.
Most moss balls will not come perfect shape in round cause they were squeezed and from a crowded tank. Some may have white spots, some yellow fur. Just change water make sure water is clean and fresh.
Be patient, it will do its own job to get better then perfect. (The process is just like healing your broken heart… that’s not what I’m saying… ok it is.