my son is 13 years old and hitting puberty like gang busters. He read and saw the movie "A Fault In Our Stars" now every change that is going on in his body he believes to be cancer. Luckily I found this web site and it has helped to see other with the same problems he is experiencing. My question is, he has a small bump on the left side of his head, which I have concluded is a result of his bicycle helmet. He is a healthy active boy. Could you please reply if only to say, the changes are normal.