Red spots on bearded dragon

Question
My boyfriend has a young bearded dragon that lives singly in a large aquarium.  Awhile ago we noticed a large red spot around his left hind leg.  With time it started to fade.  

Over the holidays, we transported him to my parents' house for about five days.  He was in a much smaller aquarium but still had his UVB lamp, shaded areas, and had the same diet.  When I took him back home, I noticed his red spot around his leg was brighter and also noticed a large red spot with some yellow on his belly.

Neither of us know what it is or if we should be concerned.  His behavior has seemed normal and nothing that we can think of could have caused any bruising.  Any help is appreciated.

Answer
Hello Rachel,

Can you post a picture of him for me?
Do you have any heat rocks or anything in his tank that could have burned him possibly?
I need to see a picture of this for further evaluation of him, please.   
What type & brand of UVB light are you using, a florescent tube bulb or a compact/coil light?  What type of basking light are you using, a bright white light or a colored light?
It could possibly be mites.  What type of substrate are you using currently?  Sand, tiles, paper towels?  

I would get some betadine & dilute that down & bathe him in it.  Then use some neosporin or polysporin ointment on the areas that are affected.  Do they look like they are getting infected?

Tracie