Going to MATY and searching for 'sunburn debugger' - something you could have easily done yourself, since the very topic you linked to says the lot debugger is from that site - I found this topic: http://www.moreawesomethanyou.com/smf/index.php/topic,10626.0.html which explains how to use the lot debugger to remove a sunburn. I don't mind helping people, but you've got to admit it would've been a lot faster for you to do that instead of waiting for a response.
So, just download the debugger, put it on your Sim's lot, select the affected Sim and use the Fix -> Sunburns and Tans option, and if the Sim isn't supposed to be burned any more, they won't be. If they're still burned it's because they're supposed to be burned, and you'll have to wait for it to go away. The lot debugger can be found here: http://www.moreawesomethanyou.com/smf/index.php/topic,72.0.html
Open the zip and place the package file in My Documents\EA Games\The Sims 2\Downloads. If you have a lot of content, it's best to keep all hacks in a subfolder inside your Downloads folder, so they can be easily removed if you install a new expansion or have a problem. If you need more detail, this guide is great (the title is supposed to be funny): http://www.sims2wiki.info/wiki.php?title=Game_Help:Downloading_for_Fracking_Idiots