Thanks for the kind words everyone, and they worked! The vet called me right after surgery and she said that Punkin did really well and is now resting. She removed the tumour successfully and did not find any other. There was very minimal blood vessels as well (I guess that's good news!). Although she did tell me to start on his ear antibiotics again as they're not fully yeast-free.
My bf should be at the vets any time now to pick him up, then Stig at the daycare, then home. Hopefully it'll be an uninteresting night.