Question: Bought a Used JP6 with Rough Fret Ends

So I purchased a used 2014 JP6 with very rough, tear-your-fingertips fret-ends. The Interwebs agree that the fretboard shrunk due to humidity changes – fix is to put in a case with humidifier.
I’ve had it in a case with a humidifier for 3 days now but no change.
Anyone know how long this could potential take?
Thanks!