I have dealt with so many cysts, abscesses, and masses that I now do as much at home as possible. And actually, only younger, not overweight, and healthy (no URI symptoms at all) rats are ever considered for surgical removal by a vet. In most cases it's either treated by myself or allowed to take it's natural course until it adversely affects the rat, mainly tumors with complications or involvement with any processes or organs. Once a tumor is having an impact on any of these things, the rat is vetted and, if necessary, euthanized. I have had anywhere from 2 to 12 rats at all times for many years, most are rescues I temporarily foster and rehab (behavioral or health) and ready for adoption. If they don't ever become adoptable, they are then failed and I give them their forever home. So I have had lots of rattie health issues that I've dealt with at home. I do no invasive procedures and nothing that would produce more than superficial and transient pain. And of course I have Metacam and a few other pain meds on hand, even the ones not easily obtainable. But any pain that needs a vet to treat is immediately rushed to my vets. (Yes, I have a few, for varying reasons and issues). Anyway, remember that cysts are generally not painful, but abscesses are. Masses and growths can be but don't have to be. Know the signs your rat expresses that denote pain so you can recognize the amount of pain she's in, that's the most important thing to learn. Best luck to everyone. Time for me to check in on my sicklies.