What Causes Painful Bruise On Shaft That Moves With Skin?

Hi. My two year old uncircumcised son just was diagnosed with balantitis from a probable yeast infection that hadn't cleared up fully a week ago. His penis was extremely swollen and red. After 24 hours on Bactrim and an anti fungal cream, (and a significant amount of discharge) it looks almost normal, but he has what looks like bruise now on his shaft that moves with the skin (it's not under the foreskin). Is this normal? Could it be bruising? He says it hurts when I touch it. He's 2 years old and 26 lbs.