I took Chili to the vet today about the irritation and small bump on her belly. Turns out the bump is her navel! I'm so relieved. I didn't even know that dogs had a visible belly button. The irritation is being caused by her constant licking of that area of her body. She has a lot of nervous energy and is nipping at the skin on her legs and licking on her underside a lot. The vet said that she's developing some infection in her skin, and he gave me amoxycillin to treat that. We're just going to have to figure out how to stop her nervous habits! Any suggestions? We've tried switching toys out, putting food inside one of those little toys where she can chew on that instead, and playing really hard with her while we're at home (to tire her out).