What is this pimple on my penis?

i just shaved down there ind there is an extremely sensative pimple like thing with a short hair in the middle, is it an ingrown hair or something? what should i do to get rid of it? its so sensative that if my belt even touches it slightly i REALLY feel it. the pimple thing is hard too almost like a little ball under the skin. and no its not an std.|||sounds like an ingrown hair that got infected. try to pull the hair out, squeeze it, rub antibiotic cream on it.|||not sure...but I think its just an ingrown hair|||S.T.D