If this worm is in you 100g tank, I wouldn't worry too much about losing 1 worm. As suggested by others above, live worms would be best fed as a treat a couple of times per week.
Too many lost worms could cause issues with increased ammonia levels if the worm decomposes in the tank. Keep an eye on your readings to be on the safe side but more than likely everything will be fine. I've lost a worm or two in the past, no issues.