IN WINDOWS:to find the game save,first see if you have permission to look hidden files/folders,now enter in C: (Or the file that have windows installed)\Users\"YOUR USERNAME"\AppData\LocalLow\Fishlicka\Juice Galaxy\saves\ and you found juice galaxy saves,the bad thing that if you wanna change the skin but not create a new game,is that you need how modify
the file,in other comment i will teach you how modify the file,but first,create a texture using this file for example
Page that i get the image https://fishlicka.itch.io/juice-galaxy/devlog/189761/015-character-customization
(IF THE TEXT HAVE A ERROR,IS THAT I FROM LATAM OR ARGENTINA)