Straight to the point - a lot of my female vampires have the vampire-blue body, but an ordinary-coloured head. Is there any way to fix this? (If it makes any difference, I'm using a custom skin.) I have tried transforming and then curing them of vampirism multiple times, and I have tried changing their clothes and appearance, but neither of these have worked. I have all available patches installed.

I also did a search, and found this thread:
http://www.modthesims2.com/showthread.php?t=90788

which addressed pretty much the same problem. I followed the moreawesomethanyou link in the 6th reply, which led to another link (in the 240th reply) saying that the problem had been "Fixed by Shaklin", but alas, the link was broken and the site was in German anyway. It's been a year since that thread, is there now a way to fix this annoying glitch?

It sounds like you have defaults that are conflicting with each other. backup your entire My Docs/EA Games/Sims2 folder then go through the steps in this faq: http://www.modthesims2.com/article.php?t=139718

OK, I tried that, and nothing's changed. In fact, now all vampires are half-blue - male and female, custom-skinned and Maxis-skinned. Surely there's a hack or some costume makeup or something that can fix this?

Are these female teens? Then it is a Maxis bug. They have a typo in one of their skins.

Get the "vampteenbugfix" from http://shaklin.net/shaklin_vamp_teenbugfix.zip

If it doesn't work even with a completely clean Sims 2 folder, then the chances are that the game data files are messed up. You could try replacing them (objects package and the Sims 3D files) as in this thread, or else reinstall:
http://www.modthesims2.com/article.php?t=134921

I tried Shaklin's fix, but it didn't work. The thought of re-installing and all the hassles that go with it make me groan, so I decided to try and create my own workaround the problem by making some costume makeup in the vampire-blue shade (which would cover the entire area that's still showing up skin-coloured on all my Sims.) If anyone knows of someone else who's already made this, a link would be appreciated to save me the trouble.
Meanwhile, forever the one with problems, I'm now having issues with the costume makeup (these vampires are turning out to be very troublesome!) Should I head on over to the 'Create' forum to ask about that?

You could always try replacing the data files, as I explained above- it's easier than reinstalling.

I tried replacing the data files; it still didn't work.