Bump on penis

Patient: I am a 18 year old. About two months ago i notice a bump under the white spot on my penis. i went to two doctors. One said it’s blister and the other say it’s veins. what’s bothering me now is if it’s blister it would have been gone by one and if it’s veins why is there a bump.And i can hardly feel the bump when it’s in the erect mode and the white spot is especially obvious when i pull my foreskin back. Please tell me what it is!