tortoise arm trouble

by jodi
(san marcos, ca)

I just wrote a previous question regarding this tortoises arm that is swollen unilaterally. The tortoise can walk, eat and all that, but I want to be sure it is not in pain. The swelling creates a tight fit from the tissue of the arm and the shell. What is this? It is a tumor? It feels full, and hard to the touch. I just adopted the girl and am unfamiliar with what needs to be done.