Most hot keepers do not keep antivenom. Injecting your own antivenom can be just as fatal as the snake bit itself. Antivenom is very costly and does not have a long shelf life.
Some hot keepers do self immunization with diluted snake venom. This is like getting a vaccine from your doctor. You start off with small amount and gradually work your way up to larger amounts. This allows your body to produce antibodies to the venom and in return your blood is the antivenom. You are taking place of the horse/sheep used to produce anivenom. I do not reccomend ANYONE to try this with out the help and guidance of an individual that has successfully performes self-immunizations.
The worry is that your body could have a reaction to the antivenom or the diluted venom, in the case of SI, and this could be just as fatal as the venom itself.
Matt