feel somehitng bits like when touch skin on balls

it started about 8 months ago.when i touch penis i felt like small bit on the skin.same skin colour.but felt like just under skin.then with time it get bit big..and it stop.but it's not big.feel when touch.then about six month ago i found on the balls i feels same sort of things.it was in January.
but i didn't do anything.i had STD test,blood and things in may..they said all ok.but i didn't say about this as i felt it's nothing to do with STD.
so i still have those ,and can feel  when i touch balls skin..
i don't like that..as not nice feeling when have sex..and it not nice..
is that something dangerous..or know thing?
what should i do?