My female mouse has a small lump a little below her neck, but above her legs, on her underside. Her sister seemed to have something like this, and died of a very serious infection that reached her head (and ultimately, her brain I'm guessing). Gatorade, the female with the bump, has been in with a male, but I doubt it could be an absess; Dexter will do anything for her and is very gentle. I am wondering if it is genetic, dangerous, what ever you can tell me. Is there a way to fix it? Please, anyone with knowledge about this, help me!