mikelove9: I did some searching but didn't really find anything. Are there any mods or anything that let you overwrite a mutagen you already used? I'm upset that I already used 2 crappy mutagens and I didn't know that it was permanent =/
Unfortunately, no. I do not know of any mods that allow you to switch out mutagens. (I think the game does warn you that mutagens are permanent, but it's easily missed.) I have been asking for this functionality to be included in a future patch, but it's up in the air as to whether it'll be implemented.