Hello, My son is 2yrs old, when I was going to give him a bath last night I noticed he had a bruse or sumthing right above his hip. Its a little knot under his skin and its tender to the tuch. He is a verrry active child, it seems like the only time it bothers him is when I tuch it, I dont know if I should take him to the doctor or if i am over reacting, Help Please!!!!!