So Boomer has settled in very well he is living in the top half of the DCN with Boris and Chase, I have even caught him snuggled up with Boris. He very rarely whimpers anymore and he is such a sweet boy.
His lump turned out to be an abscess, we were keeping an eye on it and last week we noticed that it was starting to get red spots, this weekend during cage cleaning I saw it had formed a scab so I gave an experimental squeeze and stuff started coming out, it looked like brown toothpaste. Yuck! I can't believe how much came out. I am very happy for him to get rid of it.
I'll post some photos of our squishy boy soon.