Daily masturbating isn't considered unhealthy. It's only bad if you masturbate so much that you're damaging your penis or ruining your life with it somehow. It's been shown it's healthier for the prostate to masturbate than to not. Neglecting hygiene is a lot unhealthier than masturbating.
Unless you were hoping for a MASSIVE list of everything that could possibly cause any sort of bump, you might want to describe it better. (Or go to a doctor or clinic, where you could get real advice.) Exactly how big? Color? Where? What's it feel like? Does it hurt or itch? How long's it been there?