Sweetie, don't worry too much. Most doggie bumps I've known are harmless - they do LOOK scary, though. Gracie (the mostly Great Dane my family had) had one on her side that SEEMED huge - especially in that oh-so-smooth Dane coat. But it was just a "wen" said her Scottish doc, and he promised it didn't hurt her, so there it stayed throughout her extra-long life, never causing her harm. The vet probably saw it and knew it was harmless a week ago, so forgot to mention it. You can call them Monday and double-check.