You need to just resubscribe.

1. Close the game. Wait until it's really closed (1-30 seconds).
   See Steam status to be sure.
   
2. Unsubscribe the mod. Wait until it's really removed. The Steam must say at the bottom:
   "DOWNLOADS
   N of N Items Complete"
   
3. Subscribe the mod again.
   
4. Profit.

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P.S. Also you may check the files in workshop folder but it's overkill.
If you really want to check files...

Zomboid workshop folder:
C:\Program Files (x86)\Steam\steamapps\workshop\content\108600

The mod folder is just the mod ID:
2864043248
(you can remove this folder instead of unsubscribtion, but later the Steam will check all the mods again)