Pet Garter Snake

Question
QUESTION: My boyfriend has a pet garter snake, for almost a year now. It is a wild snake.It is very healthy in appearance, and active, and has always eaten readily. This week however, the snake will grab it's food, "a worm", mouth it a bit, them let go. Last night, we noticed a bit of watery bloood around it's gums, but no obvious injury. He has no mites, his eyes are clear, and his tank is clean, dry, and has a substrate made for reptiles.

ANSWER: Hi Lisa,
  Garter snakes can be surprisingly hard to keep healthy compared to more widely kept species. Do you notice any mucus coming out of his mouth? If so, you will have 3 signs of mouth rot. Not wanting to eat can be a sign of pain. The blood can also be a sign and mucus would be the third. Do you notice his gums / mouth skin area being loose? Google mouth rot and view some of the treatments. If it continues, take him to an exotic vet.

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QUESTION: Would the snake , if say he had mouth rot, still grab the prey, then spit it out? What would the remedy be for this

Answer
Yes. If his mouth is painful, he would do this for sure... Here is a good article on mouth rot.

1
Look inside your snake's mouth to check for signs of mouth rot. These include thick mucous, holding the mouth open, pus, bleeding, cheesy discharge and excessive saliva.
Step2
Treat the mouth rot if it is a mild case using an anti fungal medication from a pet store or veterinarian. The bottle should indicate that it's intended to cure mouth rot. The medication will probably be in a powder form, which you need to dilute with water. Using an eyedropper or medicine dropper, wash out the snake's mouth. Follow the package instructions.
Step3
Take your snake to the veterinarian if the mouth rot seems to be a severe case or is not getting better after you treated it with the anti fungal medication. Your snake likely needs further care. The veterinarian will take a sample from the snake's mouth and possibly a sample of blood to test for the severity of the infection.
Step4
Realize that if the infection is extremely severe, your snake may have to undergo surgery to have affected tissues removed. Injected medications may also be necessary.