Juvenile athritis?

My oldest daughter, Emma, burnt four of her fingers in a brownie baking incident a few months ago. Since then, she has had issues with one particular thumb. It keeps swelling up, no redness or puss, just unbelievable growth and of course, pain for her. She has complained about it off an on since.
I brought her to the ped's a month ago about it. She had an x-ray of her thumb tooken, along with some bloodwork. All comes back fine. Ped knows we have no insurance and says the next step is a specialist and it will be pricey. She said that Emma wasn't in any imminent danger and if we wanted to wait, just to call and she would give us the recommendation to the specialist then.
Of course, I didn't want to wait, my kid was in pain but I had no choice with no insurance.
Well, poor Emma has gotten worse so I called today about seeing the specialist. The ped set it up for this Friday. I am hoping that it is nothing, but how can it be when I have seen what it looks like. On top of it all, her foot on the same side has been swelling and hurting her for the same amount of time too.
Coincidence?