How to make the mod work (The process is a bit long but bear with me):
(Also, if you already know how to use the Skin Changer mod, skip to step 4)

1- First, download and install the Skin Changer mod by EBro912 from here:
https://steamcommunity.com/app/1049890/discussions/0/3372657330752356676/
or
https://steamcommunity.com/linkfilter/?url=http://https://www.unknowncheats.me/forum/unity/516244-little-witch-nobeta-skin-changer.html

2- To make sure it works, enter the game, load a save file and press Insert on your keyboard.
If a menu with green text shows up, you did everything right so far. Close the game and follow the next step.

3- Copy the "BirthdaySuit" folder (or any other variants you'd like) and paste it inside "TextureMods" close to the game's executable.
(If you haven't created the "TextureMods" while installing the Skin Changer mod, do it now.)
The next time you load a save file and press Insert, there should be an option below called "Birthday Suit" (or whatever variants you chose). Don't click it now.

4- Slide the bar to number 6 (the BearMuppet costume) and press "Set Skin". You should have the bear costume on now.
Next click "Hide Costume", this should leave Nobeta in her underwear.

5- Now finally for my mod, just click on "Birthday Suit" and voilà!

I'm not an experienced modder so texture swaps like these are all I can do so far. The texture isn't perfect yet so I plan on updating it in the future.
Looking forward to seeing what interesting mods other people can do in the future!

Changelog:
v1.1- Improved the normal version and added a tanned version as well. Just copy, paste and overwrite everything.
v1.2- Added a bandaid version.
v1.3- Renamed the "bandaid" version for "tape", added a REAL bandaid and succubus tattoo variants.