bump on iguanas jaw

Question
I got my iguana from a pet store and the longer i had it and talked to people the more i was told that pet store isnt a very good one. I am not sure how old it is, the sex it is, or if it even came from a good place. But here recently i have noticed a bump on its jaw right under its mouth. It doesnt seem to affect its eating or be sore. It eats really well actually. I just dont know what could be causing it.

Answer
Hello Nicole,

Can you post a picture of the bump for me?  That would be helpful if possible.
You can also post a picture of the ventral (belly) side if you can, so I can see if there are any enlarged femoral pores which would indicate a male.  How old is he or she, any guess at all?
My guess just based on a brief description could be an abscess or a cyst, or possibly a bone deviation from metabolic bone disease.  Is the bump hard or soft?  It might have been banging its face or snout up against a tank, possibly.  
What type of UVB are you using currently?  Are you using calcium supplementation as well?

Tracie