[LunarBerry]

Oh I know that feeling, we had our old jack russell, Chloe, have a bump on her shoulder removed about a year or two back. Found it was cancerous but the vet was pretty confident that it wouldn't come back and that the type it was was pretty common in old dogs, but just to keep an eye on her just incase. She's been much better afterwards and is spritely but before hand it did seem to appear fairly quick (like we notice a smaller bump that got bigger in 1-2 months) and was causing her a little pain in the beginning (she got mad if we tried to touch it), it didn't seem like it hurt her around the 3rd month when we decided to get her surgery. The bump was also fairly firm.