Thanks for writing to us.
From what it seems, your friend is having an inflammed sebaceous cyst
Sebaceous cyst are benign cystic lesions containing thick oily pale yellow/ cheesy discharge underneath skin. The treatment is excision of the lesion. Right now as the lesion is inflammed, do warm water compresses twice in a day. Apply antibiotic cream over it twice in a day. If possible consult a doctor to take oral antibiotics
for faster resolution of infection. Once the infection and inflammation phase is over get it surgically removed.
Hope that helps.