The skintone panel and the other non-core features of XCas are the same for 1.38-1.48, but the slider hack is a core mod, and must be compatible with 1.47. So you need to redownload the slider hack from MTS if you haven't already. That should fix everything right up, hopefully.
Core mods will *almost* always have to updated, because they have to match the patch number of your game or they will not work.
1.48 is an exception. Patch 1.47 and 1.48 are internally identical, however, so for any others reading, all core mods will work for both 1.47 and 1.48. This has been confirmed by Twallan, Pescado, and Cmar.