Your problem needs a proper treatment, it is not going to heal by it's own. The bump may be a small abscess, Pilonidal Sinus
or a simple cyst
. As it is painful and at a site where a small infection can cause much problem to patient.
In my opinion consult your General Surgeon
as soon as possible. Your doctor may prescribe you a course of antibiotic and anti-inflammatory drugs. In rare cases it may need drainage
, depending on the problem and clinical examination.
Go through the treatment as soon as possible.