Lump On Baby Rats Heel?

Question
Greetings,
I purchased a baby male bershire rat the other day.  He seemed like his brothers and sisters, running around and having a great time. But today, I noticed a soft lump on his heel. One heel is skinny (normal) and the other is soft. I touched it and he chirped, like it hurt him. He seems to be walking okay, and he eats like a horse (plums, rat food, bran cereal really anything I put in there).
The only problem is he's very young. Is there anything I can do for him at this point?

Thank you.

Answer
It may be the beginning of bumblefoot. Is it red and inflamed looking? Kinda like a blister? Try to keep it clean and if you haven't yet, pad your shelves to offer him a little more support (basically, bumblefoot is a pressure sore that pops and gets infected). Keep the cage clean, so that it doesn't get more irritated, and keep an eye on it. If it begins to swell more, get bright red, weep or ooze, or he begins to worry it, you need to see a vet and get some antibiotics for him.