Son plays alot of football and has recently become aware of a painful foot when he walks on it. He had one that i treated with bazuka then 4 more have appeared but Baxuka didnt work. Took him doctors and the prescribed Salgel which stung and didnt work wther. He has 5 on one foot and very close by his little toe. They are panful and look awful. The big one is black in the middle. Never seen them before. Advice please????