Help us please!

We have a kitten that 4 or 5 weeks old, and she has this bumb on her stomach that I'm starting to panic and my mama doesn't know what to do! Someone said it might be fluid or something that has to squeezed out carefully a cleaned regularly, but it can also be something else, and I'm scared to accidentally hurt the kitten, I don't want to accidentally put her in shock, if anyone can help me, please tell me!