My 2 year old smashes finger really bad. I don't think it's broken. It's a little swollen and it looks like there's liquid coming out from his nail.

You can't tell if a finger is broken or not without an X ray. Liquid, I don't know, unless an infection moved in.
Broken fingers need attention within hours if you want the bones aligned in their proper position and a splint applied. Otherwise you are stuck with a lumpy finger for life, many times. Once scar tissue has formed internally, there isn't much to do unless you have surgery, and surgery is not usually an option because it just creates more scar tissue, and is too expensive for too little effect.