<s>[INST] Just had a cyst removed from left buttocks.   The surgeon said it had a pus sac underneath and he said he put a chemical in there to see if it would work.   He said I would probably have to have an outpatient surgery to ubclog a gland which would take about four months to heal.  He never specifically said what it was. [/INST] Hello, thanks for posting on HCM.The gland he might be referring to is probably ‘sebaceous gland’These glands are present over most of the part of skin and helps secrete oily material or ‘sebum’ to keep skin lubricated and water proof texture.Sometimes the opening of these glands get clogged or blocked due to factors like- dust, trauma, bacteria etc. and cause increase in the secretions which accumulates inside. If it gets infected with skin bacteria it forms abscess and pus formation.Or the accumulated sebum forms a cyst as it happened in your case. I hope I answered your query well.Thank you </s>