If a venomous snake somehow gets it's own venom in its body, will it be affected by it?

Question

Here is a hypothetical situation I had been thinking about that sparked my curiosity:

Let's a snake is just slithering around, not being attentive for some odd reason. It happens to pass a mouse, in which it didn't see (this is all just hypothetical), and the mouse freaks out and starts to run. When it does, it trips over the snake's tail, and, not knowing what is happening, the snake snaps back bites the mouse and gives it a good dose of venom. (Now, to my question).If the snake ate the mouse, would it's own venom, now in the mouse, hurt the snake?

(Since they are native to where I live, let's say the snake is a Water Moccasin)

Answer 1

An excellent question. This fun mental floss article addresses that question, but from the perspective of one snake biting another snake:

Snake on snake violence

“The conventional wisdom is that they have circulating antibodies in their blood,” says Stephen Mackessy, Ph.D., a Professor of Biological Sciences at the University of Northern Colorado and an expert in venomous snakes. “This would protect them from their own venom, as well of venom from another snake in their own species.”

Hypothetically, if a speckled rattlesnake bit another speckled rattlesnake, the immunity they’ve built from being exposed to low levels of their own venom—kept in glands behind their eyes and secreted when they bite—would protect them from a fatal wound. (Even though the glands are closed, they still contain blood vessels that allow the venom to circulate in their system, causing mild exposure, Mackessy says.) But a speckled rattlesnake that meets up with a cobra might have a different day entirely.

The same principle should apply to venom ingested in dead prey. Antibodies against the venom would protect the snake. For what it's worth, I think your way of phrasing the question is more interesting and relevant than the way it was phrased in the mental floss article.