If shinki feel lingering guilt that they haven't resolved, it can cause both the shinki and their god to suffer blight that won't wash off.

[Hakkai takes another bite of his eggs, chewing and swallowing before he continues. His tone is mild, but he's not about to reassure Goku that it's not a big deal.

After all, it is.]

It'll hurt, but what's more dangerous is if it spreads to cover too much of the shinki's body. There's a spell called an ablution that can be used if it goes too far, but it's better to talk things over and resolve them before it gets that bad.