Hi and welcome to HCM.
You shouldnt freak out because it usually has nothing with hygiene. This was probbaly cloggeed gland which became inflammated an dthis is almost the same as pimple on the face. IF you notice more of them you should be tested for STD
and treat with antibiotics. If this is the only then you dont have to worry,just keep this area clean and dry,dont wear syntetic underwear that provkoke sweating and thats it. Wish you good health.