I got into a server set up by my friend. The world disbled the online mode such that everyone (even with pirate account) can get into this server.
Since the online mode is disabled, I download the mod CustomSkinLoader in order to make my skin to be shown to everyone including myself.
Now there's something wrong. I cant see my skin when I turn on Wurst, and when I delete Wurst in the mod file (the CustomSkinLoader mod kept opened in the whole process), I could see my skin again.
I've searched online about this issue and found out that someone else occured the same problem, and the explanation is that Wurst would prevent other mods such as CustomSkinLoader from obtaining player names, making CustomSkinLoader impossible to display skins and cloaks on various CustomSkinAPI website (e.g. SkinMe, BlessingSkin, TLauncher, LittleSkin).
After testing, it was found that the display of the skin was as follows when the two modules were turned on and off respectively:
DISABLE CustomSkinLoader, DISABLE Wurst: Skin ×
DISABLE CustomSkinLoader, ENABLE Wurst: Skin ×
ENABLE CustomSkinLoader, DISABLE Wurst: Skin √
ENABLE CustomSkinLoader, ENABLE Wurst: Skin ×