I redownloaded the Showerproof Mesh and I installed the Showerproof mesh. Could the mesh be corrupted for the Showerproof skin that I downloaded?
Did you assigne a sim with the skintone and took it ingame to check when hes showering?
If the sims bottom dissapears, you dont have the correct mesh installed.
If the default body is showing up you dont have the correct skintone assigned.