Sorry I didn't see your posts until now. I'm glad to know Daisy is back home after her surgery. Your tender, loving care and our prayers for her will help her heal faster.
Carina had surgery for cysts three times, the last one in her back was as big as the one you described. Fortunately, they were all just fatty cysts, nothing dangerous, but I know how hard it is to think that our furry friends are in pain. Please give Daisy a very gentle hug from me with many warm wishes for a quick recovery.