No great options really...prevention is the best, from now on, feed on a "plate" of some kind (paper plate, cardboard box lid, etc).
You're right that your snake may still be in "feed mode" & bite you if you approach, & handling her now may get you a regurge, but what I'd personally
do if this was my snake is this: fill a clean spray bottle with cool water (a new bottle preferably, NOT one that has contained cleaning products etc) & give
her some sprays to her face. This may help her flush out her mouth, but mostly it will "change the channel" so she's not thinking "food! bite the incoming!"
Then proceed to help her wash out her mouth in a bowl of water: leave her in place in cage, don't handle her, just remove her hide if needed to reach her,
and slowly put a bowl of water up to her face. Pay attention to her moves & mood, all snakes are different...as I said, this is just what I'd do. She probably
won't drink on her own, but if you pour a little water over her face she likely will, & the substrate will either fall out or get swallowed in the process of her
drinking.
As far as I know, if she swallows a little of this substrate it won't hurt anything, but I hate to leave substrate stuck in their mouth simply because it can set
things up for a mouth infection. BTW, you aren't the first one...this happened just recently to someone else who posted here.![]()