What Causes A Sty Like Growth On A Teenager's Face?

my 13 yr old son has gotten this sty like growth on his face..it is under his eye lid and just above his cheek bone..it is not a pimple.it looks just like how a canker sore looks on your tongue but, picture it on your skin on your face..what is it? one of my neighbours said its because he has to much calcium, is this true?