Thanks for posting your query.
The lump you are having is most likely a boil- called a furuncle
in medical parlance, or it can be a anorectal sinus
This will take long time to heal without treatment and may increase in severity to cause more pain in coming days.
So it is worth while to get examined by a local physician and get treated in time.
Hope I have answered your query.
If you have any questions I will be happy to answer.
Please close the query if you have no other questions.
Wish you a good health.