You can use it from the inventory as opposed to at a shrine, but that doesn't seem to have any real impact and doesn't cure the rot.
Source: I actually did this with my first one, like an idiot...but I do have a stock of them and have yet to actually cure the rot due to the number of bosses I've come across and wanted to beat before clearing it.
Oh wow, didn't realize that haha. Thanks for the advice
Also seriously I barely get the rot now. I feel like I don't get it at all fighting bosses. I've only ever gotten it if I die from mobs.
Heh its the opposite for me, I only got it from attempting
Lady Butterfly