>>> It is easier to pull one from the closest receptacle, or whatever, than to pull a new wire all the way back to the panel in a finished place.
1. You could pull both hot and neutral from the receptacle and connect that to the portion of the circuit in question after making sure both the original hot and its accompanying inoperative neutral have been disconnected.
2. You might double check all the receptacles etc. on the original daisy chain feed to see if you can find the problem with the neutral. Notably convert push-in-and-stick connections (backstab connections) to screwed on connections.
When cleaning anything including baby diapers, it is better to sweep off or scrape off as much solid and semisolid material as you can first. (1) Less cleaning fluid or detergent needs to be used, (2) Less of a mushy mess which in turn means that bleaches or disinfectants will be more effective.