my 4 year old grandson started 2 days ago, after wearing new shoes to a wedding rehearsal, limping and not putting any weight on one foot. this got better the next day, but came back at the wedding reception the next day. he was wearing a different pair of shes but they were new and stiff and tight.his dad took him home early and found that bruises appeared above the shin just about ankle high and right in the middle of the leg on both feet. he continues to avoid puttin weight on both feet, on in particular and asks to be carried. he is a very active child and crys because he can't be active. any ideas what this could be?