Capturing snakes to use for medication is biblically prohibited. If it is done to protect yourself from a snake bite, it is not biblically prohibited.

Chapter 316 Section 8

You are prohibited from capturing one of the 8 creeping creatures. If you make them bleed or even just give them a black and blue mark, it is prohibited as it is 'chovel’, making a wound.

With other creeping creatures that are not from the list of 8, if you make a black and blue mark, you are not biblically prohibited since the blood just goes right back into the circulatory system.

Chapter 316 Section 9

If you find biting bugs on your body, you can pick them up and throw them off.