One hand blindly fishing around in the wrong log, one impulsive grab at an unknown species, and you risk a lot of pain, ridiculously expensive hospital stays, lost fingers or limbs, or death...
Again riding this theme for the OP as /u/TheyShootBeesAtYou likely knows all this stuff and more.
When I go out herping here are some things I do for safety (a few are not bite related). I'm not saying you must do any or all of them -- just that I do them.
I wear tall hiking boots that cover my ankle and go about halfway up my calf muscles. Then jeans or canvas hunting (thick) pants. This is all very minor protection but something I always do in territory of venomous snakes (I hear this is better for short fanged hot reptiles, though I'm around rattlesnakes which have longer fangs, but maybe there is some small chance they might hit a baggy part of the pants or thick part of the boot and not penetrate my flesh). I always looking where my feet are going to land for places that could be hiding snakes (don't blindly step over logs/rocks). I don't wear leg protecting gators or knee high snake boots, but I have considered them for piece of mind.
Finding snakes is usually hot work, so I always bring multiple water bottles in a small backpack (the new double walled insulated ones are AMAZING), and also have a huge cooler with ice water or iced beverages in the car parked at the trailhead. With all the mentioned clothing I wear -- I sweat a crazy amount, and so I need to drink a lot of water. Many times I would think I've brought enough water, only to be searching for the nearest gas station to get more after a trip. Bring more water than you think you'll need! Truly cold ice water after hours of hot herping is such a luxury.
I take somebody with me. My wife, a co-worker. If one of us gets bitten, potentially the other may need to safely drive us to the nearest hospital. I don't think its enough to tell somebody I'm going out into the desert and herp alone in rattlesnake country.
Have a hospital plan! Its important to know the name and general area of the nearest hospital before herping. Often the places I herp are out of cell tower range so I can't look up directions to the nearest hospital while out in the field. Make sure its not some unfamiliar tiny clinic that cannot handle snake bites. Calling around just takes a few minutes to figure this out.
This one depends... some areas I herp seems to have no ticks, other areas I'll rack up more than a dozen or more in a day of herping. Just be mindful to scan for them. Lyme and other tick carried diseases can be terrible.
Probably other things I'm forgetting. Be safe!