Dont know if you mean skillpoints get negative when you give yourself more skillpoints. If you do then you have to change the total skillpoints. Not anything else. Cause it counts how many skill points you used out of your total skillpoints.
You go into the editor and change total amount of skillpoints on a character. Never give yourself points in any other way than that.
Click on Equipment menu in game, then go the character you want to change the points.
You will see the total skill will change for each character in the trainer editor.
It works great.
Yeah, thanks everyone for your replies. I did see your post about it after I'd made mine, and did what you suggested, thereafter.
Thanks again, everyone! 💛