If the snake was eating before there is no reason to stress it out further by assist feeding it.
My questions are going to be these.
What size enclosure is the animal in?
What size hide (pics are helpful) are you using?
Are you presenting the enclosure?
Lets get some pics of your setup and I'm almost 100% sure that its a security issue. Anytime a baby that was eating gets a change of environment and stops eating its almost always a security issue.