Feeder health concerns - grossed out!

[Vibes]

Okay so I defrosted a rat for my boy Murmur that I got from a local reptile store specializing in snakes. When I inspected it I saw that it had a huge growth on its lower abdomen off to the side, I don't know if this was a tumor or cyst or fat deposit but I've never seen that on a feeder before. It's body was also covered what at first I thought were it's nipples but when I looked closer I realized they were randomly sprinkled about its body and were oozing puss. Maybe they were pimples? Just wondering if anyone else has ever had this happen and what it could be? I discarded the rat but am wondering if that kind of thing is normal and would have been safe to feed Murmur? Comments and additional insight appreciated, thx!