This is kind of a weird issue and I have no idea what's causing it. Basically, when my sims shower, their hair changes (and then back when they put clothes on). Ordinarily, that would be a CC error, but this is happening with my game/store hairs too.

I have the latest patch, and I recently went through to fix the rig error that some items were having (using Grant's fix) but the hair thing was an issue before I did that.

I didn't see anything about this in the help section but if I overlooked it, please point me in the right direction! I'm just hoping I don't have to reinstall, it's such a pain.

This might be a weird question, but do your sims have different hair styles set for different outfits? That still wouldn't quite explain how the nude hairstyle got unset, but it would be interesting to see what happens if you change a sim's hairstyle, then lock it so that it's used on all outfits and send the sim to the shower.

(I'm assuming you went through the FAQ here: http://www.modthesims.info/wiki.php..._3_Game_Problem ? )

I had the same issue, and I solved it using Nraas Master Controller.
It's updated for patch 1.29 and you can find it here, and I suggest you to download also the cheats package, that you can find here, which adds more options to the mod.
When your sim is under the shower, click on him/her and choose Nraas - Master Controller - Stylist. Once there, you can change their hairstyle and get back to the game.

Hope it helps! Bye~

@Ghost: It was on several different sims, but I never use multiple hair styles for some reason. That's why I thought it might have been a CC issue at first, because sometimes they're not set right. But since it's EA hair, idek. I haven't gone through taking all my cc out since I dealt with the _rig issue, so I guess I can try that again.

@Hellena: Thanks for the advice! I wonder if I can do that with cheats instead of installing a new mod... well, only one way to find out!

Another Nrass mod that works well is the Dresser, from there there is an option to set a current hairstyle to all outfits...that will also include any work outfits your sim might have that changes their hair. http://nraas.wikispaces.com/Dresser