First off: I’m so very sorry. I know how much this hurts. I know how much it sucks. My biggest regret was not letting my cat go earlier. I couldn’t be with him when he crashed, and it absolutely destroyed me.
It’s always, ALWAYS better to let them go too early than to make them suffer for our need to keep them with us. We owe them that for all the love they’ve given us.
Self isolation is a big sign. So is the refusal to eat, the general restlessness. It sounds like he’s miserable. I would give him the best day you can, and let him go gently.
Hello,
It is not possible to diagnose a lump or bump by a picture. This should be done with a veterinarian at an in person exam. After the exam a list of possibilities. But to truly know what it is you need cells or tissue from the mass. Like a biopsy.
Of all the possible things it could be a histocytoma is on the list. Ask them about this.
I hope this helps.
Krista.