Yikes! Ouch! I've happily avoided being bitten by any venomous snakes, so far, but I know from close friends that the bites hurt like hell. Not fun at all.
I have a remedy that might help, @papa-pepper, and is based on a lotion that is made by a company in Alabama that is reputed to have helped at least one dog badly bitten by a rattlesnake on its nose.
The story goes that the dog was bitten on the farm, far from any vets, and as the only remedy the farmer had close at hand was the lotion, that's what he used. He rubbed it well into the bite wound, then rushed the dog to the vet hospital over an hour away, not knowing if his best friend would last that long.
Long story short, not only did the dog (a German Shepherd) survive, but he recovered fully with no ill effects, which the vet likened to nothing short of a miracle, the bite being so close to the brain. He went on to live a long and healthy life.
The lotion contained organic sulphur and magnesium as its primary ingredients, both of which are needed by every cell in the body, and are reputed to deactivate poisons, including snake venom.
My version, which I adapted for a bad tick bite I had, and which subsequently got rid of poison ivy blisters on my VERY susceptible husband, uses 3 tsp of DMSO as the source of organic sulphur, 1 tsp of magnesium oil for the magnesium, and 15 - 20 drops of frankincense essential oil, as it is one of the most healing oils on the planet.
I put them all into an empty essential oil bottle (dill) that I had on hand, and shake well before using. It works so well that I now always keep it on hand.
I don't know if it will be quite as effective this long after the fact, but I know that in any case it speeds healing, and a little goes a long way. Literally a couple of drops is usually all that's needed at any one time.
I will say that the last time I made a batch of several bottles, they solidified, and I have no idea why, as I hadn't changed anything. That said, one bottle I had scraped some out of with a wire subsequently re-liquified, and has the same effects as the stuff I've made in the past, so it doesn't seem to have affected its effectiveness at all.
I hope that it helps, and in any case, if you have as much poison ivy around your place as we do, not to mention ticks and biting bugs, I think you'll find it is worth keeping on hand as well.
Good luck and be blessed!