The hide feature needs an unhide option.

[Afacey99]

I accidentally hit the "hide song" button in the middle of a workout and can't remember the name. Such a stupid thing to not have the opportunity to undo or "unhide" it. If there is please let me know, ive tried everything. 

[MadmanOnWheels]

It's there. It's in the options, and it's right on the right side of the song bar (or whatever you call it), to the left of the 3 dots (options button). Just tap or click it.