HELP PLEASE!!! I found a BABY MOUSE who WONT EAT ;-;?

My mom went out to mow the lawn and sure enough a mouse had put her nest inside it. The nest flew out and all of them died except one. I went and bought him a heating pad and some formula and an eye dropper, and he wont eat the formula... How do I get him to drink it? I dont't want him to die D: