Analysis paralysis around mutability

I'm creating a program that lets you edit the metadata of of audio files (e.g., "artist", "title", etc.). A Track has a metadata HashMap<String, Ediit> where an Edit contains the original and current value of the metadata (this allows decoupling metadata edits and file saves). I'm very new to Rust, and the issue I'm running into is finding a compiler-compliant and clean way for my app to maintain a mutable reference to an underlying Edit while the user is editing. The original way I tried solv...