My bf has a problem?

he is uncirsized ( in colombia they dont do that there ). at the bottom of the tip of his foreskin there is a nub of skin the size of a marble. it isnt discolored or painful. its just there. he has had it since he can remember. this has come to both of our attention that this isnt normal, i have researched and looked at other uncirsized ' and it isnt common. we are affraid it might be serious. does anyone know about anything like this? please dont leave me responses saying ew or gross. im asking this question on here because i love him and care about him and i need help. :) i really appreciate it.