Pit vipers, such as the rattlesnake, copperhead, and cottonmouth (also called water moccasin), are snakes that can inject venom when they bite. They leave one, two, or three puncture marks on the skin, but you won't always see any marks.

Symptoms of a pit viper snakebite usually appear within a few minutes to a few hours after a bite and may include:

• Severe, immediate pain with rapid swelling.
• Bruising or blisters near the bite.
• Nausea or vomiting.
• Trouble breathing.
• Changes in heart rate or rhythm.
• A metallic, rubbery, or minty taste in the mouth.
• Numbness or tingling around the face or in the arms or legs.
• Signs of shock.

The severity of symptoms will depend on the type of snake that bit you, how much venom was injected with the bite (envenomation), the location of the bite, and your personal health risks. Even if you do not have symptoms within 8 hours of a bite, continue to watch for symptoms because you could have a delayed reaction.

• Dry bites (no venom injected) do not need to be treated with antivenom. At least 25% of bites are dry.
• Mild envenomation bites may cause mild symptoms, such as mild bleeding, pain, and swelling at the bite.
• Moderate envenomations are more likely to cause symptoms of severe pain, swelling of the whole limb, nausea, vomiting, and weakness.
• Severe envenomation symptoms include severe pain, severe swelling, trouble breathing, moderate to severe bleeding, severe allergic reactions, and signs of shock.

It is important to remember that a snake only injects part of its venom with each bite, so it can still hurt you after the first bite. Don’t risk another bite by trying to capture or kill the snake.