Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain a hard painful lump on the inside of butt cheek that is painful can be most probably
Perianal abscess that has not started draining..
It is commonly due to infection and clogging of glands in the skin or accumulation of bacteria over the skin leading to formation of pus under the skin leading to formation of a painful lump..
I would suggest you to
consult a Proctologist and get evaluated and a clinical evaluation is generally sufficient to diagnose the cause..
You can be advised to take a course of antibiotics, anti-inflammatory painkiller like
Ibuprofen and also topical application of antibiotic and
steroid ointment..
Injectable antibiotics and steroid can also be given for faster recovery..
In case if the lump is considerably large and painful he can also do
Incision and drainage followed by antibiotics and painkillers for faster relief..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.