My wife is an ER nurse, and the accepted treatment for cotton mouth, copperhead, and most rattle snakes is limited to tylenol or motrin for pain and observation for 8 -12 hours. They rarely do much else unless there is severe pain or swelling. Antivenom is only used as a last resort as the side effects can be worse than the bite. They did have one guy loose his right arm and half of his left arm to two rattle snake bites this year. He was drunk and playing with it, it bit him on the right arm. He decided to catch it to take to the hospital. When he picked it up again it bit him on the left arm. Long story short snakes and stupidity don't mix.